A GPC device should be able to develop and compile programs directly on device without any external dependency. That's what you get with Windows, Mac or Linux.

HTML+CSS is considered Turing complete [0], but we wouldn't call that a complete GPC environment.

[0] https://stackoverflow.com/questions/2497146/is-css-turing-co...

It is silly but we arbitrarily classify computers as general purpose or not based on the market segment they go after. Phones, video game consoles, e-readers, TV sticks… and also cars and some refrigerators could run user provided code, but the general expectation is that it is OK to locked them down for whatever reason.

Many Logitech peripherals have Turing-complete chips (ARM processors), but no one is claiming that my mouse is a general purpose computing devices.

Apple is selling a system made of a combination of hardware they make and the software running on top of it.

There's really no reason a laptop or a desktop should be considered as some special device that's required to not be locked down either.

It's just a combination of hardware and software running on top of it

To be honest, a lot of end-user problems would go away if they were restricted to a child-proofed version of computers.

In a sense they have been doing that to themselves by not knowing how it works, or how to write code, which already restricts them to things other people made.

They then further restricted themselves by migrating most of their work to mobile devices that run software that only the vendor realistically can be in charge of (mostly due to NDAs for the IP Cores like baseband and SoC, but the amount of kernel patches you get with Android hardware is insane... good luck trying to get a recent kernel for those).

As a result, there are mostly behaviour based problems that remain, most technical problems have disappeared. That is an effect (and limitation) that we cannot deny.