Reality TV is cheaper to produce, requires no real talent and the "stars" have little bargaining power, so they initially get paid way less than a sitcom or drama actor would. MTV (https://www.marieclaire.com/culture/g3538/mtv-shows-you-totally-forgot-existed/), Discovery Channel (https://www.quora.com/Why-is-the-History-Channel-and-Discovery-now-peddling-pseudoscience-and-reality-shows-instead-of-you-know-airing-science-and-history), History (https://screenrant.com/fakest-history-channel-reality-shows-real/), Bravo (https://screenrant.com/best-bravo-reality-shows-ranked/), and VH1 (https://www.buzzfeed.com/laraparker/i-love-new-york) all hopped on the reality TV train and oversaturated their schedules with it.

Unpopular opinion

Not a lot of people are watching any kind of TV. So these channels fill their schedule with a lot of forgettable programming. I think these channels make their $$$ by teaming up with streaming services. And the programming dept doesn't give a hoot whether such channels have lost their soul and abandoned their roots.