Over a period of 17 years, Cavendish has competed in 23 Grand Tours and won 56 stages. Even including GTs he crashed out of, that is an average of 2.5 wins per GT for a period of 17 years (racing against three generations of the best in the world, trying to do the same thing as him). Cavendish has won 165 races. He is multiple World Champion on the track, an Olympic medalist, World Champion on the road, points competions in all three Grand Tours, has won a Monument (often called "the hardest to win" by pros), and seven other classics. I believe he is now also the oldest winner of a stage in the Tour de France and the longest career of winning stages. This was all while enduring some major career struggles, illness, injury, and public shaming. People still act like there is something gimmicky or illegitimate about his record.
I'll say again that his win today was a *very* good one, sprinting both against fast young field-sprinters like Phillipsen and Jakobsen, and crafty veteran hardman sprinters like Kristoff and Demare. He was tactically superior and faster than everybody else to the line.
The sporting analogy that is actually coming to mind for me is George Foreman during his boxing comeback. Like Cavendish, George had a stage in his early career where he had a personality that the public hated, while also being considered irritatingly invincible at his sport. He had a couple of embarrassing losses and the public dismissed him as a one-trick pony who couldn't actually defeat well-rounded boxers capable of navigating his big knockout punches. During his comeback, the big names of his generation (considered the heavyweight division's greatest era) were long retired. Re-watching those fights, the pundits (including during his victory over Moorer) won't stop talking about how slow and ponderous George looked, wishing somebody would please make the old man retire. Suddenly, he was heavyweight champion again (20 years after losing the title) during what many consider the division's second greatest era. Many people *still* saw it as gimmicky and somehow less legitimate, and he retired at 46 when he got robbed against Briggs. George's willpower, tenacity, longevity, *and* skill were unbelievable, but his critics wouldn't see it then for various reasons.
I think that Cavendish's willpower, tenacity, longevity, and skill are also legendary. History will recognize it, though many of his contemporary critics never will.
Cav isn't Merckx, but that's apples and oranges. His record is what it is and it stands alone.