The build up of Lena stalkfap is very slow compared to how much money she can make right away with Seymour.
I think is safe to say Ivy is into some shady shit.
I think it might have more to do, with the fact that Ivy has more stuff to spend her money on, than Lena does.
We have only a limited amount of things to buy for Lena. If you're getting Seymour's money and Stalkfap money, and other money on top of that, then you've got more money than you need.
It's only if you don't take Seymour's money, that you may not have enough to buy all the outfits, tattoos and toys from the sex shop ( or most of them at any rate).
It took Lena several months to start posting any really naughty content on Stalkfap, whereas Ivy pretty much started off doing that immediately. On top of that she's the lead gogo dancer, at one of Baluart's top nightclubs. Every night she's probably gaining more potential customers for her Stalkfap account. Which gives her a huge advantage over Lena, when it comes to making money from it