Are those compatible (except for form factor) with those Apple uses?
Why even develop SATA Express when this solution does the job?
Do you suggest that this is the standard everyone and Apple should adopt?
The only thing that's terrible here is your weird, constant driving need to bash things you barely know anything about in order to... what...
I didn't find your truck versus car analogy helpful either. For what was that... in order to...
First of all, Apple is using the PCIe bus where ever it is needed. All the heavy load goes over PCIe and even the external TB ports are some PCIe plus useful features. There is no faster and more versatile port than Thunderbolt anywhere. So if anyone has the trucks to move a mountain, it is the Mac Pro. And it is also the sleeker computer. So you can have a nice car that doubles as a powerful truck.
The only part of PCIe apple is not using are those dimensional standardized expansion card slots. What is so good about them, that they can't be phased out as obsolete technology? Backwards compatibility can't be an issue, if upgradeability is your goal. Surely you don't wanna replace your dual GPUs with older ones? And going into the future, why stick with what has become obsolete a long time ago?
Graphic card makers have already worked around the standard in using two slots for one card. And adding more fans because the positioning of the card is stopping the air flow, instead of leading it around the hot chip. Also these cards have become too heavy for holding in with one screw at the top, so the PCIe x16 slot needed a little plastic latch to avert the card from falling out by itself. And because of all these little fans the whole box needs to be noise-damped.
And if you do want to change your configuration, you have to shut down your computer, unplug it and screw it open. And don't forget to double check if all the pins fit correctly before you close it, put it back in its place and hope it's still booting. I don't get, how this experience can be better than plugging in a plug-and-play Thunderbolt peripheral? What are those use cases, when 20 Gbit/s are not enough and you need raw PCIe? You are making this up, just to disagree.
Not being IBM-compatible is the least of Apples problems. In the contrary, it's a huge benefit. Someone needs to not follow the compatibility madness. The new Mac Pro form factor was only possible because it does not support PCIe expansion cards. And you wanna give it all up, just because of third party pricing greed? No! If they are not yet copying Apple, they should start with it right now. I can't wait to see, when Intel claims to be the inventor of the UltraTrashcan.