Coming from francophone Belgium, I've had the chance to watch my first cycling at age 7, whether it be Bore de France OR the major classics. And, of course, here, everybody has heard about Cancellara or Bettini, even if they aren't particularly interested in cycling. The RTBF has always broadcast all major classics, Bore de France and the Worlds. I couldn't see the Giro until Eurosport broadcast it, that was in 1998 and then I watched it BRT when I really mastered Dutch. But there's always been talk about the Giro in the news or whatever.
However I'm sure that cycling's popularity has been declining massively over the decades. I still remember a classmate when I was at primary school in the early nineties, saying that many households would stop their daily activity to watch a cycling race. I don't think he would say the same now.
In the 1950's cycling's popularity was at an all-time high in the traditional countries (Belgium, France, Italy). Actually, the bike itself was still the most popular means of transport (champions like Coppi, Van Looy, Van Steenbergen, Kübler or Bobet were all delivery men, using their bike for their jobs. The multi-talents could NOT go unnoticed). Then the vespa came up and gradually motorsports started being popular. Then tennis in the Borg years. I own an old Miroir des sports (French mag) from August 1963 about Beheyt's "betrayal" at the Worlds (with Van Looy). In it you have 19 pages about cycling, 3 about Track & Field, 8 about football, 1 about tennis and 2 about the other sports.
I've often asked my grandpa about cycling from the forties. Do you remember Marcel Kint? "Of course !", he replied. And then I would ask him if he remembers about the old tennis aces. He would tell me he had a vague memory of Jaroslav Drobny but that's basically it.
Also popular culture is full of reference to cycling. In the French cinema, I've recently seen a film called Le mouton à cinq pattes from the fifties in which Fernandel plays a character that is "as popular as a bicycle champion". This quote would be ironic today. Surely he would be "as popular as a football champion" (or a pop star, lol)
In the Italian cinema too, Don Camillo is sometimes compared to Bartali. Alain Delon was offered Coppi's bike on the shooting of Il Gattopardo.
In Belgium, I've been told that when Merckx was racing, people would all gather round TV shops to watch him or in pubs. Also I've read Belgian Sorrow, which is full of reference to Bartali, to Kint, ...
We can't understand anything about the prestige of this sport if we don't remember that it used to be the absolute MOST POPULAR sport in Western Europe for decades.
I don't really regret though because if some of my friends don't give a damn about pro cycling, there are always to have a ride, and that's the most important.