That's patently false, of course other competitors can improve on a tablet computer. Apple isn't the end all/be and there's always room for improvement.
While you mention the CPU that apple is using is the best there ever is, I suspect that intel chip sets can and will give it a run for the money. The thing is you're equating perfection to a device that isn't even available for sale yet. No one has it in his hands yet.
Overall competitors are not pissed but rather see an opening to market their devices where apple cannot. A true tablet computer, not an over-sized iPod Touch.
Here's the problem with that: it's been tried and simply doesn't work.
I know I keep banging on about this around these parts but I beg people to stop and THINK before demanding a 'true tablet computer'. You're dealing with a 10" screen at a maximum, backed up with a mobile processor or at best a CULV device, relatively limited graphics, storage that must be solid state and a price point that has to make sense when compared to modern laptops. That spec is going to limit what you could do with a 'true tablet computer' in horrible, horrible ways.
Take, oh, Photoshop for example. First you'd need to redesign the entire interface from the ground up so that it a) fit on the screen properly and b) could actually be used by fingers. That's a huge step right there. Then you've got to recode the entire application to be lean and fast in order to stand a chance of getting decent performance out of the processor. THEN you've got to figure out a way of handling a large image file which can take up scary amounts of memory. And then, somehow, you need to make the entire thing play nice with the rest of the OS.
That's a vast amount of work to get a common productivity tool working PROPERLY on a 'true tablet computer'. Yes, you could run the standard desktop app but good lord that'd be a horrible experience. I really doubt it'd be useable actually and as for getting any work done on it, forget about it. Sure, you could add more hardware, maybe pop a 13" screen on there but there's three problems with that:
1) You loose the slim and light tablet form factor (and probably generate enough heat to require active cooling).
2) Battery life goes to hell
3) It'd probably still only give you a passable user experience rather than a good one.
It's the applications that are the sticking point with Tablet PC's, always has been. Even if Windows 7 had the best touch interface the world has ever seen (it doesn't btw) it still runs standard Windows applications which are built around keyboards and mice and gigabytes of RAM and tens of gigabytes of storage and fast multi-core processors. Try to cram that experience into a tablet and you end up with something heavy and power-hungry which produces a far worse result than the equivalent laptop. The only place a device like that can survive is in specialist markets using custom software built around the device. Now in a few years when we can get the same power as a Core 2 Duo in the equivalent of the A4 it might be a different story but you'll still have to overcome that interface issue.
Apple have taken a different approach with the iPad and it's just about the only one that's got a hope of working as far as I can see. The hardware is nice and, from initial hands on reports, seems quick using iPhone OS. The rest is up to developers to make use of the device and free up its potential. Whether they will or not remains to be seen of course.