It used to be the same with x86 computers, but over time a standardized interface was developed.

ARM is already getting something similar, but most companies aren't interested, precisely because they're perfectly fine with the restrictions.

The ptoblem is that all the phone manufacters don't release any drivers, neither close or open

And yet they're all the same

Capitalism

Imagine owning a laptop and not being able to install linux without the manufacturer permission.

Fairphone 6 ?

There is a reason we are putting up with decades of legacy stuff still from the original x86 architecture in PCs... the compatibility of hardware and the standardisation even if it's through several extensions build off each other is unmatched.

ARM architecture might be much simpler but you constantly need hardware specific adaptions, which makes support for different mobile devices this mess.

One thing I really dislike about the Mobile ecosystem is how much different each device is to each other.

I thought you were sarcastic when I first read this part, since way back when phones used to be innovative in both hardware and software. The current market offerings are all carbon copies of eachother with a strong trend towards converging into the exact same lineup.

Multiple cameras, one in front, 2+ in back. A power button and two for volume. Reader apps may hijack it for scroll. Gesture movements. Fingerprint and face id. Less and less conusmer freedom in software choice. Irremovable battery. No removable back plate. A rectangular brick. A near-100% display area. No headphone jack or SD card, with SIM on the way out.

Covers the vast majority of offerings on the market, with a few slight adds/subtracts. Dumbphones are a rounding error.

This definition covers even tablets, and it isn't even deliverately vague.

Without much experimentation and development on the hardware front, no wonder software's behaving exactly the same.

There just isn't enough interest for proper innovation and experimentation.

And we're not even talking about iphone

I think you don't really understand how hard it is to standardise everything. Just because IBM managed it in the 80s doesn't mean it was easy.