Well, to be fair they did do exactly that with D&D 4e and the GSL. Which bombed spectacularly, as their audience continued to play 3.5 and Pathfinder which continued to use the OGL.
This is actually WotC learning from their mistakes. If they launched 5.5e with a regressive and user-hostile licence, people would just ignore it and splinter the community and hurt the new edition.
Instead — the way wotc is attempting here — they blow up the old editions entirely and shut down all their competition in one legal maneuver. Existing customers have little recourse, they still enjoy ttrpg with their friends and d&d has significant brand strength as well as being the only company left publishing. Nerds will whine but the company now is now well-positioned to be the sole competitor in the increasingly profitable digital future. They don’t have to spent 10 figures on the next dndbeyond, they can just sue them. They don’t have to built a better vtt than foundry, they just shut down foundry and theirs is better by default — tada!
They may have underestimated how loudly nerds like me are whining, and voting with our wallets. And perhaps also o overestimating how successful their legal shenanigans would be — I’m not a lawyer but so much I’ve read from legal analysis suggests wotc is in a dubious position and unlikely to succeed here.