i've seen some models doing their own thing, just posting wall PPVs at moderate prices (15-20 bucks) and getting 10-20 likes (likes number is relevant because you can only like a PPV post if you have bought it).
then they go the agency route with the usual slimy tactics with the DM spam, "VIP club" and the girlfriend roleplay, and they have single posts with $3k+ in tips.
one such model did some livestreams before and after going with an agency.
before, each stream she would barely break $100-$200 in an hour.
She recently did one (first after going agency) and in about 40 minutes she went above $1k.
Unfortunately, agencies are so widespread for a reason. Not only is it an actual skill to get people to buy shit at a higher price, it actually takes time, because most of these dudes are actual losers that CRAVE the attention that they think they're getting from one of these models and not some random dude AI generating DM posts every hour.
from how i see it, for the models the actual "job" has always been to keep up with the roleplay and pretending to care about their dick or whatever, not taking pics

eepoShrug: Agencies just take care of that part and likely do a better job than the girl to get the most money out of lonely dudes, making it a net gain of both more money (even counting the agency commission probably) AND less time pretending to care about dudes they obviously don't care about at all.
sadly, it works too well.