> Electron apps don't have the theming support that Winamp did

Pardon me for answering this at length, though it's tangential. But I actually know quite a bit about Winamp.

On the contrary, Electron, being based on Web technologies, offers a much better way to do theming, via CSS. Of course, most apps don't expose this capability to the user, but they could.

Winamp's theming support, at least in Winamp 2, was actually very crude. A Winamp skin was just a collection of bitmap images (BMPs, I think) that made up the main Winamp window, the EQ window, and (if I remember correctly) the borders of the playlist editor and media library windows. And some windows, like the main preferences dialog and the windows opened by various plug-ins (e.g. SHOUTcast), weren't themed at all; they had a generic Windows look.

And it's fortunate that the most complex parts of the Winamp UI (ignoring the media library) were not themed, because as far as I recall, Winamp never implemented proper accessibility for its custom UI. (I don't have Winamp on my current machine, so I can't easily verify that now.)

The Winamp main window was completely inaccessible with a screen reader, except for the title, and I guess we wouldn't have even had that if it wasn't needed for the Windows task bar. That wasn't so bad, because every function in that window had a keyboard command, and because Winamp is an audio player, the user could usually hear the result immediately. When toggling shuffle and repeat, Winamp provided a way to get the state of those flags through a window message; I don't know if they did that for accessibility or some other reason.

I don't recall if blind people had a good way to use the EQ. Perhaps they could adjust it with the keyboard and just listen to the results rather than looking at the sliders.

IIRC, the playlist window didn't use a standard Windows list view for its contents, but it was still more or less accessible in practice. All actions in that window could be done with the keyboard. And it used standard GDI text rendering functions to display the contents of the playlist. All good Windows screen readers could intercept GDI function calls (or their counterparts in kernel mode) and build an "off-screen model". This was good enough for knowing what text was in a window, and which text was highlighted. So a blind user could access the playlist editor. (Note that no screen reader has attempted to do this for more advanced graphics technologies such as Direct2D and DirectWrite.)

But if the rest of the UI, such as the preferences dialog and the SHOUTcast plugin windows, had been skinned... well, blind people probably wouldn't have adopted SHOUTcast so eagerly, from the day it was first released. As far as I know, no screen reader, even with an advanced off-screen model based on intercepted GDI calls, could provide good access to a fully custom UI, with buttons, text fields, combo boxes, check boxes, and so on, unless the application implements an accessibility API (for Windows, either Active Accessibility or UI Automation). In fact, the reason why Microsoft created Active Accessibility, the first accessibility API, was because they needed it for the dialogs in Office, since those dialogs use windowless controls.

But, bringing this back to the original comparison with Electron, with Electron you can have an application that's both fully skinned and accessible, as long as you follow web accessibility guidelines. So keep that in mind if you're inclined to reject the bloated Electron and use (or create) your idea of the perfect, lightweight, themable GUI toolkit.