Yes.
At least N times the work for N platforms.
Fewer developers, harder to recruit.
Cross-platform options like Qt are not modern/pretty enough and sometimes aren't that much thinner than Electron (depending on how well written the app is). Java/Swing/SWT is also quite bloated and looks terrible.
Development is much slower in languages like C++. Other languages are not cross-platform or have immature/buggy cross platform support. How's ObjC on Windows? C# on Mac? They exist, but nobody uses them.
I really think we're in a UI dark age. Native UI development has gone backwards compared to the ease of WYSIWYG GUI design 10-20 years ago. Go back and use the VB.NET GUI builder from 2004 and be in awe at the incredible productivity you could achieve. Platforms are more fragmented today too. There is even fragmentation on the same platform! Do I use Qt or GTK or (insert one of a dozen others) on Linux? WPF or Windows Forms on Windows? Cocoa or UIKit on Mac? Which one will MS or Apple kill tomorrow? ... or I could just say fXXk it and use Electron and be done with it.
This is 100% the fault of vendors. If you hate the bloat blame Microsoft, Apple, and Linux developers, not people who use Electron.
Edit: mobile UI development is less fragmented but it's not really that great either. You get no choice in dev tools and the code is absolutely unportable. I see higher-level web or web-ish views/libraries/frameworks taking over there too. It's already happening.