That's a ridiculous comparison. Those jobs aren't bringing in revenue for their employer.
People who compare entertainment, and sports salaries to jobs like being a doctor, or a cop don't seem to understand that those professions don't make big bucks because they're not making other people richer. It's not about the importance of the job.
A baseball team can pay a layer large sums of money because that's their market value, and they have that kind of money because of the draw of the players.
The best apples to apples comparison would be boxing, where PPV main event fighters are making millions in most cases. (But lower down the card can make a measly amount of chump change)
Next best would be lucrative team sports, as the athletes are the main draw making millions for their franchises. If I recall correctly the revenue/profit share is about 50/50 between the athletes and the organizations, and again if I recall correctly, I believe I heard that the UFC gives out 13% to fighters. (I can't post a source but 13% would be a fairly random number for me to fabricate out of thin air and I have a distinct memory of that figure)
Bottom line, if Dana is able to drop over a million on his kid's birthday party then main event fighters in title fights should be getting WAY MORE than 150k.
A cool million for a title fight sounds about right, at least 500k, and that should be flat rate, none of this you get paid half if you lose shit. Kelvin fought like a damn warrior and came up just slightly short, he bled and went to the hospital, certainly got a concussion if not multiple concussions as he was dropped several times after having been hit hard enough to destroy his equilibrium.
As someone who knows that sadly many many boxing world champions retire broke (especially older generation fighters and lower weight classes) and have physical issues, bad knees, CTE, headaches, insomnia, pain, addiction etc... I would like to see fighters be sufficiently financially rewarded for the damage and risks they take for our entertainment.