The hell are you guys talking about. Cycling was way way bigger back in the day than what it is today. Road Cycling is a mere fringe sport these days.
It's kind of a paradox, right? Cycling is more global than ever, and more professional than ever, but it's a smaller sport!
Back in the day there was a week of flat stages. But domestiques were often less strong, as the péloton had a greater disparity between the strongest and weakest individual riding, and the fields drawn by the different races were different with much stronger regional focus, which attracted fans to the side of the road - no Euskaltel-in-Roubaix or first-year-Greenedge-in-the-Giro outliers, with smaller teams who were more passionate about those races and added something to them entered instead.
Also when for most stages only the last part of the stage was broadcast, the race could weather a lot more of those flat stages, especially given that the break often got a lot more rope in those days before the big teams started reeling them in, they didn't just sit at an easily bridgeable gap that was held at the same level all day, so there was a bit more tension involved in the chase. While the sprint stages were hardly the most exciting part of the race back then, they were also less formulaic than flat stages now as a result, or at least less repetitive in the formulae they used.
Nowadays the professionalism at the top of the sport is greater than it's ever been. The flip side of that is that it has homogenised the calendar, with the same teams bogarting over 80% of the major race invites, which limits the colorfulness and exoticism of each individual race bringing its own character to the table, and means that all the strongest riders will congregate in those teams, especially since Pat McQuaid closed the loophole that Cervélo and BMC found that enabled them to essentially get all the benefits of being ProTour without the drawbacks of the compulsory flyaway races. This means that the general field of a given major race tends to be stronger than it was 30 years ago; but simultaneously there is greater equality in the bunch, meaning more riders hold on for longer and more control is exerted over racing. Especially in flat stages, which are now more or less interchangeable in any World Tour race.
Simultaneously, we're now treated to start-to-finish broadcasting of every stage at major races. While I appreciate that we can look at historic feats that happened before TV went live, such as Heras on La Colladiella and Contador on the Collado de Hoz, and say we need to tune in lest we miss something, the fact is that we really don't need 4 hours of live broadcasting of a sprint stage; even more, we don't need to
watch 4 hours of live broadcasting of a sprint stage. The old broadcasts got it right for these stages: get in, establish who's in the break, how far they are away, show clips of them duking out the metas volantes and GPM, watch the chase, catch and sprint. There's no need for hours of them in a holding pattern just because we
can broadcast it.
The increased professionalism has led to a series of templates which work for almost any World Tour race, and have resulted in a reduction in the variety, and reduced the time gaps between the major contenders because they're fighting mano a mano less often, and for a shorter time, save for the occasional outlier where somebody gets desperate and goes from deep. This is also the major driver for the reduction in TT mileage - not the TV coverage. The TV viewing figures were a leading reason for why Zomegnan went mountain stage frenzy and eventually lost his job, but if TTs were being marginalised because of the televisual spectacle, they'd be showing sprint stages in the same way they used to. And in the world of Unipuerto stages we don't really need full start-to-finish broadcasting either. Maybe the early 2000s Giri are the way to go - full broadcast start to finish of selected stages - queen stage, a couple of mountain stages, the one with the Cima Coppi - and last 90 minutes or so of everything else. As long as they keep filming so that we can see if we missed anything important (the split in L'Aquila 2010, Contador's attack in 2012 - I think Pajáres would have been one of the stages broadcast in full in 2005 if this was the template), and it can be put into the start of the broadcast in a "the stage so far" 5 minute package, this would be beneficial I feel.
And the thing is, I'm not meaning for people like us. We're hardcore enough cycling fans to be discussing in the forum. I mean for the casual fan. If the first time I saw cycling I switched on and saw 4 hours of the péloton riding serenely 3 minutes behind a breakaway of people I'd never heard of and the commentators didn't really sell as having a chance to win, I wouldn't even have tuned back in. Really, that's where things like the Hammer Series have come from, this idea that regular cycling is boring, and needs spicing up. Regular cycling isn't boring, if the people behind it accentuate its positives and hide its negatives, and unfortunately they aren't doing that at present by and large, which has led people to draw the conclusion that road cycling is broken and needs freshening up, rather than that road cycling is fine but being utilised wrong, just like a perfectly good centre-forward who is not scoring goals, but it's because he's being played out of position or just doesn't fit the system of the team he's in at the time. ASO broadcasting a featureless transitional stages for four hours, or Unipublic broadcasting hours of flat valley riding before all the action is in a final 3 minutes of garage ramp climbing is accentuating the negative. Velon introducing complex track-inspired points systems to reduce the value of completing the course in the fastest time is hiding the positive (with a regular bike race, anytime you turn on the TV, you instantly know, even if you don't know anything about cycling, the objective is to complete the course fastest, and all your subsequent considerations are with that in mind).
"Back in the day", fewer races were broadcast in any great depth, too. Nowadays it's easy to reach saturation point, so people will lose patience with a couple of dull sprint stages in a row if they've already watched a dozen of them in the last month across several smaller races.