You can’t get simpler than Python and tkinter (or just strait TCL/tk.)
Packaging these without depending on preinstalled software is hard (you probably shouldn’t even bother trying on Linux, everyone there expects installing weird stuff to involve using either git or a container anyway.)
As far as I can tell the main reason people don’t use it is that it can’t make iPhone apps.
great, now you have a native client but now your customers will expect that it works offline, so now you're building a sync system for your app.
additionally, if your app has any design/layout issues, now you need to hire for people that can do visual layout using tcl/tk.
If your app consumes rich text, you're in for a real treat as you are now on the hook for figuring out how to manage that as well (in addition to serialization, you also need it to likely be emitted into some web friendly format anyway. if your app consumes some feed (say new-user facing features or whatever), you need to find some meta-format that your app can use to layout that content (or i mean, i guess you can use a webview, but then...)
if your customers are enterprise-ey, you are now dealing with some overzealous IT dept that is skeptical of your application running with user permissions.
if you're trying to push a fix/update to your users, you now need to build infra around deploying new apps as well as customer support determining if users are somehow running old versions when they report a bug.
the web is a total "mo money, mo problems" situation, but i think people dismiss how many problems the web solves for your developers on a day to day basis: easy to push updates, simple to whitelist your app's domain on some restricted network, easy add dynamic content/layout to portions of your app with stored content, (less sync resolution issues because your app probably requires network to operate) etc. Native apps have their own issues, they're great, don't get me wrong, but people demand a lot from basic apps of any stripe these days, and as those requirements increase, so does the amount of complexity that developers need to manage at all stages of the pipeline.
Oh sure yes, 90% of the things people want are really just a few HTML forms and a back end.
My point was that desktop development isn't any harder than web development. Most of what you've mentioned involve adding features and the same features would be just as dificult to implement in a web app.
>but people demand a lot from basic apps of any stripe these days, and as those requirements increase, so does the amount of complexity that developers need to manage at all stages of the pipeline.
I think most of these demands are misunderstood.
RE: "syncing": Most people just want to work with their data offline. Traditionally this was done by interacting with the filesystem rather than a thick client manipuliting the state on a server (like many modern web apps are.) There's no need for "syncing" or complex protocols.
Packaging these without depending on preinstalled software is hard (you probably shouldn’t even bother trying on Linux, everyone there expects installing weird stuff to involve using either git or a container anyway.)
As far as I can tell the main reason people don’t use it is that it can’t make iPhone apps.