In my case I have participated in few missions, fair money, all accepted. After that the gave me much more missions to do, but at at lower prices. I have stopped uploading.

I've participated in only one mission just to test it. It was 5 images that I already had for smth like 20/25 usd , as far as I remember and it took me 2h to select the images and figure out what to do. Of course, taxes were deducted from that glorious amount.

After some time I received questionnaire asking why I don't participate in missions with some pointless corporate questions, but all my answers were low payment or to much work for that money.
For 50-100 usd I wouldn't press camera button 200 times while lying in bed with my eyes closed, not mention organizing a photoshoot for 100+ different images.
As far as I recall,  the amount offered for previous missions was about the same as what is being offered now- from 12 to 120 usd for crazy amount of images/clips.

So, I am wondering what payment do you consider decent? And I don't live in much expensive country...

Regarding video Missions, I've had three so far - all extremely specific concepts/processes. Accepted none.

My thinking is, by completing a Mission we're effectively saying there is no need for this particular video content ever again – as we've now trained the AI on what this process should 'move' like. That's the part that needs training, the core movements (much like the motion capture data in 3D rendered animation). It's already proven to be able to change materials/camera angle/lighting/scenery pretty successfully.

The more we tell AI how to create these images/videos, the less we're needed. These Missions are self-defeating. Adobe is filling in the gaps right now.