I have no idea what is happening in Stake but I'm sure we are not the only players who get disappointed with their recent bonus, there must be many other players who feel the same.
I know what's happening on Stake actually. In the past, they were giving the best bonuses to the users. Gradually, Stake team started to spend money on marketing by doing sponsorship deals with players, teams, clubs, streamers, etc. Now they are spending a very big amount for marketing purposes through those methods. And they have reduced the bonuses of the users to spend those funds on marketing purposes.
Many things have changed, but as you said, they must have had their reasons for reducing the bonuses, unlike the ones we used to receive. Their marketing efforts are massive, and their allocated funds must also be adjusted, and they may have chosen to reduce the bonus allocation to users.
However, for me, it's not a big deal because bonuses are just bonuses. I mean, I usually play with my own money. I can completely understand user disappointment; that's normal.