With Electron (MIT licence) the writing has been on the wall for Qt for years now. They are on borrowed time.
I am not saying I like Electron better. I prefer Qt, even though I don't consider it to be native either. But Qt would not have died had they relicenced earlier. It's evident they will have to do it eventually. Why wait until there's no more lunch to be eaten?
"They" (Qt Company) are a commercial enterprise that mostly makes its money from license sales. Relicensing as MIT would be terrible for them. From their product policy you can clearly tell that even LGPL isn't working as they would like, but they can't get rid of that, so they focus in fields that don't like LGPL either. That's of course annoying for those of us who don't optimize for "what makes them money", but for "how can we build software best"...
How do you know it would have died? - Mind that their business is in embedded stuff, an area where Electron is no competition (putting a bit more hardware in and embedding android might be competition, but Qt runs on quite small systems)
https://www.qt.io/product/develop-software-microcontrollers-...
As an outsider it seems like the "Desktop" side seems to be a marketing vehicle, but not their bet for business (see also push for QML over QWidgets - less integration with desktop and less "native" looks, but working on cheaper hardware)
I am not saying I like Electron better. I prefer Qt, even though I don't consider it to be native either. But Qt would not have died had they relicenced earlier. It's evident they will have to do it eventually. Why wait until there's no more lunch to be eaten?