Electron has its place, but I'm not entirely certain touting Electron-powered text editors is a satisfactory success story. The success story is on the business side, IMO: it is another write once, deploy everywhere mechanism. Text editors are a very personal choice, but if I had to choose between an Electron-based text editor or Emacs in say, a developing world context, Emacs would win every time because re-purposing a 5+ year old laptop that only gets power from a solar panel is feasible with Emacs, at the cost of a steep learning curve. There are always tradeoffs.
Electron is very suitable for the particular contexts that it fits within, and OP made some salient points that there are some settings where it clashes with user demands. For the paying market that say, Slack cares about though, they are not sensitive to the tradeoffs made to run Electron underneath to the point that it hurts Slack's revenue to a level Slack cares about. This opens up an opportunity for someone else to step in and take the niche that Slack has currently declined to occupy, and that's not a bad outcome.
Electron is very suitable for the particular contexts that it fits within, and OP made some salient points that there are some settings where it clashes with user demands. For the paying market that say, Slack cares about though, they are not sensitive to the tradeoffs made to run Electron underneath to the point that it hurts Slack's revenue to a level Slack cares about. This opens up an opportunity for someone else to step in and take the niche that Slack has currently declined to occupy, and that's not a bad outcome.