I don't even mean the modern stuff. Even fairly old Windows apps can do fractional scaling just fine. WPF does it without a hitch, and it dates back to 2006. Even many WinForms apps can do it, and then of course Qt etc.
But even disregarding all that - if such scaling can be done without problems with webpages, then clearly there's no technical impediment to doing the same elsewhere. It's not like HTML is magic.
But even disregarding all that - if such scaling can be done without problems with webpages, then clearly there's no technical impediment to doing the same elsewhere. It's not like HTML is magic.