There is no "can't", it's a "don't" or "won't". Web based with a server they control simplifies the design from the developer perspective, it can also be better for businesses (more easily monetized, as a service for instance). This leads to two of the three primary stakeholders (investor, developer, user) sharing a common goal though not necessarily for the same reasons.

> I know most people would prefer an actual native program rather than a website/webapp.

How do you know that? Most people I know prefer the web, and absolutely do not want to install apps on their devices. But that is just anecdotal data from my circle. Did you do wider research to come to your conclusion?

It's more work, and I think most people actually don't care that much.

I don't want a native app. A browser app is fine for me.

We live in a world where apps are less than a dollar and most people balk because that’s not free, it doesn’t make much sense. And then the App Store takes 30% and Apple makes API and rule changes that requires rewriting code for no additional revenue.

Now multiply that lack of control by five or six…you are going to support Linux, right?

The web is universal and if lack of native widgets prevents adoption, you might not want those users anyway because they will blame you when their OS breaks your code. Good luck.