Sure. Electron or similar tech are doing a very simple thing: they're externalizing development costs by transferring them to the individual users in the form of storage costs, performance costs, and user experience costs, to name a few.
Meanwhile, Microsoft is a behemoth. Your argument makes total sense for a small shop with limited bandwidth to test. Companies like Microsoft don't get that excuse. They're simply padding their bottom line at our collective expense, and they can do it because they have extremely sticky services in a lot of areas (in this case, corporate email infra).
There's two platforms. Two. Windows and MacOS. Let's not pretend there's dozens. Why does one have to jump through hoops for two simple platforms? Just write the UI code twice. It's not rocket science really.
Presumably that would at least double the cost. Additionally, you have to find native Windows and MacOS developers, which are harder to find than web devs. Given that, it's not surprising that companies are moving toward web tech like Electron.
Does webui not require testing on each platform+browser combo? Or are we just accepting that sometimes it is going to break and not allowing the same consideration for native GUI frameworks?
Microsoft no longer seems to be in the business of putting Windows first. Since they're completely out of the mobile market, they're always going to have be a cross-platform software company now. They want to sell software subscriptions and that requires going to where the users are.
Go ahead, I'll wait.