So now I’m going to put an open source operating system on my first gen 256MB RAM iPad to run a web server and that’s the same functionality I had in 2010 when I was using it to browse the then modern web?
You could arrange it like that, sure. Webkit ships Linux builds, there are DEs that will give you a miserable but usable experience on those specs. If you really want to condemn yourself to a fate Apple doesn't support, there's no technical reason you couldn't.
Replacing the same functionality was never an inherent part of the deal though. There will never be Find My Linux or the Linux Store. The overall idea is that we put older hardware to use instead of recycling it for marginal returns on scrap. It's why they put "Reuse" before "Recycle" in the EPA maxim.
So your alternative to mean old Apple not allowing you to run Linux is to have a shitty experience running Linux on hardware that wouldn’t meet the needs of a modern consumer ?
Maybe. Apple doesn't let you put third-party OSes on iPhones or iPads, it's unclear what would happen if they did.
It would probably start with something niche like a barebones Linux port, but then it might turn into an Asahi-style project that does give the user a perfectly normal user experience. Maybe people start shipping CalyxOS-style hardened iOS distributions for people who want to further neuter Apple's control over their system. Or maybe people reverse-engineer a Vulkan driver onto the hardware and use iPads as low-power ASICs. The sky is really the limit, here.