Oof, wording indeed
"...sells patreon membership for $154,000 per month" directly means each individual membership costs $154,000.
Like saying "AT&T sells plans for $50 per month."
To answer the question of how easy, i'd say there's an insane amount of luck - just like being a viral hit on Youtube, or a consistent top model on a camsite - as there are other patreon models only making a micro fraction of that number. Not everyone can be a booming sensation on every platform.
Another thing about those speculative earnings of Patreon, Twitch, or Youtube stars - and this is what i've been told - is that those aren't exactly ballpark accurate, meaning they don't earn as much as speculated. Take that for what it's worth.
¯\_(ツ)_/¯