I used to play baseball in school leagues when i was younger, i still think baseball players are kindda overpaid. In terms of physical ability, it's not really a strenuous sport, if you get what i mean. It's not a very good spectator sport either, i rather play ball than to watch it honestly.
But they got their own stadiums, loyal fans, endorsements bla bla bla, money making machine.
Cycling has their loyal fans too, but i think the difference between them is the price of the gear.
Soccer boots are cheap enough for people to afford them, a couple hundred bucks and they last quite a while, if i'm not wrong, the Ronaldo CR7 soccer boots are like 200 bucks? That's about all you need, and a ball, to play soccer.
Baseball gloves are around 200 bucks for a quality one from Wilson or Rawlings, a ball and split the cost for the bat and you're good to go.
Tennis rackets are 300-400 bucks? Grab a ball and face a wall.
F1 and NASCAR are expensive but they got stadiums to sell season tickets, gear like key chains, watches? t-shirts bla bla bla.
Point is, stuff in cycling is too expensive for people to buy to support their team, you can't sell season tickets either because the races are outdoors. There's not much money to made from the fans and the coverage is pretty bad imo.
Cyclist should earn more money for the amount of training they do and time spent away from families, but unfortunately, there aren't many ways to get that money rolling in.