Oh believe me, I don't blame these companies for going where the money is... but I just find it funny that it is occurring even after all the talk from everybody the past couple years about how "bad" it is that WotC controls the D&D / 5E space, and that everyone should be breaking away from WotC in case they ever tried to do another OGL type of revocation again, or that WotC has broken the trust of the entire gaming populace etc. etc. etc.
At the end of the day it's always about money. It's why so many people hitched their wagon to D&D / 5E / OGL in the first place, and why so many people will get back into bed with WotC and D&D Beyond (and probably the VTT) even after all the supposed horrible actions the company took against them.
No one HAS to make 5E-adjacent material or use DMs Guild or anything like that. People are free to make completely independent and separate RPGs that have nothing to do with the D&D / 5E sphere. But they all know they ain't going to make any real money at all if they do. So they bite the bullet and strap on their waterskiis to follow along in WotC's wake-- hoping they can hold on for as long as they can and make as much money as possible before they fall off.