I used to have some very easy $5 modifications before. However, at some point, the minimum cost possible on the IPS Marketplace was set at $10 to cover fees, eventual chargebacks, payout fees, etc. That change increased the cost of all those small plugins that used to be $5.
Selling it for $5 on my site and $10 in the old Marketplace would have made things unfair for those who used it.
With every developer handling things on their own/separate sites, you might see smaller prices for minor v5 modifications. No idea if it will happen or not, it's just my thought. 🤷♂️
EDIT: @opentype also made some fair points, though.
The marketplace gave a lot more visibility to the available modifications. I still think IPS should have kept the Marketplace available, but make it redirect to the developers' sites (just like Invisioneer does). The idea included adding a big red warning about not supporting anything in it. IPS didn't think it would be a good enough solution, though. They wanted to avoid any kind of possible misunderstanding and decided to remove it all.