Probably (a big guess) is because google is interested in monetization, and getting the best payout for themselves and their advertisers they can contractually manage. You’re gonna get what google makes the most money off of before you get what you actually want to see. Just like google search.

Tiktok appears to be far more interested in making you stay on the platform and keeping your attention. They get what they want by making you an addict, for lack of a better term.