As for developers... I mean, how much of a big deal is it, really? I looked at the documentation and it didn't seem like a huge hassle. It even looks like it is automatable in your CI/CD processes via `altool` and `stapler`.
I do imagine that some people would go for that bargain, but it strikes me as short-sighted.
Besides, you can still run non-notarized binaries if you want to. The UI does make it difficult, but not impossible.
If you want a totally open computer, that's fine (to the extent you don’t spread it via negligence), but everything has tradeoffs. If you're comfortable with the risk of malware, that's also fine; but not everyone is -- and certainly not the business world.
On ios and ipad (from your first sentence) you cannot.
I think a good goal would be to scream it as loud as possible and make sure people are buying it based on this dimension as well.