Who says he's a classics rider? He won E3 Harelbeke and that is about it. He may have used the classics as an entry to road racing, but it didn't last long.
And yet the time he spent focusing on the classics is, at this point in time,
still a longer part of his career than his time as a mountain climber.
Plus, just because he 'only' won E3 doesn't mean that he wasn't a Classics rider, because the main problem was he kept crashing out of the biggest races or missing them due to earlier crashes. I mean, Sep Vanmarcke has 'only' won Omloop and Plouay - does that mean he's not a Classics rider? In fact, that was part of the reason Thomas re-focused as a stage racer, because the addition of day upon day action means variables like minor crashes can have their impact minimised, whereas in one-day races they can completely make or break a race because there's no tomorrow to make up time or conserve energy for.
When he won the Tour, people were using the comparison of Indurain as a heavier rider and somebody who had a late start as a GT climber. And yet at the age when Thomas won his Tour... Indurain had just withdrawn from the 1996 Vuelta and would never race again. The only valid comparison I could find in 2018 for his late start to GT contention was Tony Rominger, who started pro cycling late whereas Thomas had been a pro for over a decade at the time and entered a double digit number of Grand Tours without ever troubling the top 10 before becoming a winner of the biggest of the lot. But now he's four years older and putting in faster times than he did when he won the Tour.
He's not the only suspicious one at the front by a long shot. But he's the one that's hardest for me to un-see. To me, it feels like Wiggins was a case of a perfect marriage of convenience, ASO needed to replace that German audience and Sky needed a cyclist with profile in the UK to be the centrepiece of their push for success and with the London Olympics upcoming, he was the right guy at the right time. Froome was an opportunist who happened to hit his shock Vuelta success just as contracts were due and went from fringe participant at Sky to part of the inner sanctum and made hay while the sun shone until he could do that no more; after half a decade of dominance, Thomas felt like Brailsford et al just flexing, like "we are so dominant we can make a GT winner out of anybody, watch".