Despite the stinginess of the OGL, it provided legal certainty that many individuals and small game publishers used to make new games and new material for Dungeons and Dragons. Some of these product lines have been around for decades and developed their own following. One of the neat things about a cultural commons is that people can find something they kind of like and then tweak it to be just right for them, rather than settling for a one-size-fits-all approach. House rules and variants had always been a part of roleplaying game culture, and D&D culture specifically, and now the practice had official permission (even if it never needed permission in the first place as a legal matter).
The Electronic Frontier Foundation provides a neat overview of how Dungeons & Dragons seems to change in the future. As quoted, the open gaming license (OGL) used to be a promise that while the core of D&D remained in the hands of Wizards, you could extent it to you heart's content without legal issues.
The leaked changes to the OGL would remove this feature (which already had strings attached) and turns it into something more akin paying the App Store tax on iOS apps, but then for published modules that are compatible with D&D. In itself, not entirely unexpected, but the crux is that in doing so, Wizards might actually revoke the old license, leaving a lot of creators exposed and cut loose.
The OGL does not say that it is irrevocable, unfortunately. It’s possible that Wizards of the Coast made other promises or statements that will let the beneficiaries of the license argue that they can’t revoke it, but on its face it seems that they can.
I think we're just seeing the first step in the extended monetisation Hasbro and Wizards are looking at, making every interaction with the brand somehow generate an income. That in itself does not bode well for D&D Beyond, the franchise, the hobby, and the community behind it.