I think some amount of it is apathy, or modern-life time-poor induced apathy where people just want something to work and work quickly without much effort or time and so they just pony up. And with so many people not keeping a budget, $10 a month here and there or $30 once a month doesn’t seem like much if you’re not adding up all those subs combined over a month or a year or 5 years. Really, some subs could fall into the category of a dark pattern because $10 a month doesn’t seem like much compared to say $100 up front even though over the course of a year (or 2, 3, 5+ years) that sub costs you more than just buying software up front. (Think also Sam Vines Boot Theory).
I see some people are getting fed up (I’m one of them) but sadly plenty more who mindlessly keep paying more and more.