Part of me wants to be wary. The useful life of industrial machinery such as CNC mills is much longer than the lifespan of websites, so locally-installed software you own is usually a better choice.
But another part of me realizes that everyone is using Fusion360, despite the fact they have a history of taking away features to force people to migrate to paid tiers. So it probably doesn't matter.
> But browsers (and browser technologies) have documented track of being fully backward compatible up to the beginnings of WWW, and it's not going to change.
That can however be undermined if web apps are poorly built and depend on quirks and behaviors specific to a particular engine (or in some cases, even particular versions of a particular engine) in order to function.
So I would say this benefit applies specifically to web apps that thoroughly apply KISS — that is, using only the most boring, solidified, widely supported APIs and favoring robustness over bells and whistles — and make a point of testing against all three major engines. Those apps will likely stand the test of time and run even under future new engines. On the other hand, the ones with severe shiny API syndrome that only ever get tested against the latest Chrome are probably much more brittle and more likely to be broken N years after abandonment.
"Fully backwards compatible" isn't really true, and even if it were, then you're stuck using browser-based software and its myriad of inherent downsides.
People (generally) use web-based apps that are good enough in spite of the web stack -- not because of it.
I have a CNC mill made in 2006. It's still perfectly fine. It should still be fine in 2036. The most significant threat to its existence is the compatibility of OS drivers and software support in CAM tools. That and USB ports getting replaced by something else, which was a problem for earlier-generation machines that used RS-232.
Worst case - you could at some point rip out the brains and replace them.
CNC machines are somewhat basic machines really.
> much longer than the lifespan of websites
But browsers (and browser technologies) have documented track of being fully backward compatible up to the beginnings of WWW, and it's not going to change.
Which actually is much much better than any other environment you can imagine - unless of course you use (and want to use) that one frozen in time 25 year old PC. And pray nothing breaks (y2k bugs and whatnot).
If the software is open source (and works offline) you can have it functional in 10 or 20 more years. And it will be "locally-installed software you own" you want.