The closest I've come in recent years to running that sort of game is Torchbearer 2e, which uses GM-authored dungeons as a key element of play.Now, unlike you, I really enjoy running that kind of game.
However, like you, I enjoy running a number of other games - I would say at least 50% of the folks at my 5e games automatically pass on any campaign that is not 5e. They pass for precisely the reasons you mention - even though, I am not sure all of them would articulate it in this way.
But I still suspect that Torchbearer, especially as my table approaches it, is more player-driven than many D&D players (and most D&D-only players) would prefer. The players made the main decisions that established PC backstory, and that set the overall agenda for our sessions (admittedly the game makes this pretty easy, by centring "get loot" as a key motivation for all characters).
So far I've had two sessions of play out of a 6-room dungeon that I wrote up in an afternoon, and expect to get at least another session out of it. I got two sessions out of the four-room house of one of the PCs' enemies, which again took an afternoon or an evening to write up. The system means that I don't need to do any prep for the PCs' time in town (it has its own framework for town events and in-town action resolution that drives downtime action).
It's about as low-prep as I can imagine a system getting that relies on the GM to provide D&D-style content, and if I was wanting to lower the barrier to entry for new D&D GMs, I'd be taking a look at some of the methods Torchbearer uses. Which I know is a bit off-topic, but to me seems more significant in thinking about how D&D sits in relation to other RPGs than speculating about the OGL.