Unfortunately this will never happen. As a few have already said, these companies pay in shit tokens which makes it little risk for them. It's done that way deliberately, so they have little to no risk. They lose the cost of making the token ($20-100), the cost of a manager (tokens-$200 or whatever is negotiated, and they risk time to possibly sell a load of worthless tokens. 99.9% of bounties are a scam that never list or if they do they list on a shit exchange with little to no buy support.
So getting them to pay everyone in an established coin will be nearly impossible. Also like others have stated, there are plenty of no named managers who will always take a campaign no matter what their payment method is.
This proves a point I was making.
When paying with altcoin will not be allowed then 99.9% of those scam projects can not advertise on the forum. Since they can not advertise, 382 newbie account will not be created and send abusive merit to rank to Jr. The remaining 0.1% are considering legit project and they would have fair amount of budget to spend. Since they will pay cash, they will obviously hire users who have good work ethics and capable to follow instructions.
It's both way beneficial. Forum will get rid of those newbie bounty hunters accounts, at least they know that they will need to have a good account reputation to join a bounty so they will become serious. Legit projects will get organic traffic to their projects who will actually buy their offers.