YT now has channel "memberships" built in that mimic Patreon. Since it is integrated into YT you get a streamlined perks platform along with a special icon noting you are a "member" of the channel when commenting.

why/how would youtube axe Patreon platform use?

Using Youtube for Patreon videos, generating costs for YT that don't have a revenue/monetization component.

https://www.polygon.com/2017/9/28/16380186/youtube-patreon-d...

https://mashable.com/2017/09/28/youtube-outside-links-partne...