All of that is fine, until you can't upgrade the bus, and that becomes the limiting factor. And, when you upgrade the bus, you usually cannot use existing cards (easily). Upgradable items are usually good for two, perhaps three generations before the rest of the device is obsolete. Which may be a fine goal, but if the cost of the device doubles between upgradability and the upgrades themselves, it becomes a wash at two upgrade cycles and only profitable at three. That is a risk, and one I've seen burn people when they are caught buying an upgradable item that has no upgrades made for it.
let me answer the profitability issue first. we chose to re-use legacy housings, sockets and assemblies precisely because to do otherwise *would* result in this becoming a profitable venture only at cycle 3. there's a company in the U.S.+Taiwan which has had $USD 100m investment to create a 100mm x 70mm x 10mm modular PC standard. we've had *zero* investment.... and haven't needed it! the CPU Card development cost us under $10k. the tablet: $6k. getting new plastic done for the card because we're re-using PCMCIA metal casework from a product that's been made for the past 10 years straight: $6k.
so you're thinking inside-the-box, i feel compelled to point out :) we'll go into "profitability" with the first 10k order!! everyone involved has been working on a commission-only basis for the past 4 years on the project. there *are* no investors or banks to pay off. the first lot of profits will go straight back into the project and will begin to fund and reward the free software developers and other people who have been helping us out over the years, and that will happen pretty much immediately.
regarding the upgradeability and the durability of the standard: there's one factor that you've not taken into consideration, and it's the power requirements of faster interfaces. 10GbE over copper takes SIX WATTS, just to push the signals over those 4 twisted-pairs that's just... insane. as people have wanted faster and higher resolution screens, VGA has fallen by the wayside because at 75 ohms impedance, driving 3 lines at 200mhz and above in *analog* is just way waaay too power-hungry.
but look closely at the interfaces selected for EOMA-68. RGB/TTL (24-pin), I2C, USB3, Gigabit Ethernet and SATA. are any of those particularly critical that they be ultra-ultra-ultra-ultra-ultra fast? no not really. what are they connected to? well, they're connected to peripherals i.e. I/O. do you really really really really need an 8096x5000 resolution LCD panel on a 7in tablet? no not really. do you need a 10000Mbytes/second SATA hard drive on a 10in $150 laptop? no, not really. do you need 10 Gigabit Ethernet on a portable device where battery life is important? no, you don't.
so you're thinking of upgradeability as being all-important and the be-all and end-all of computing appliances, and i think you'll find that it really, really isn't that critical. at the apple end of the market? sure, there will be people who will always go after apple products, and the great thing is: just like microsoft's absolute-insane-latest-and-greatest processing and memory requirements have pushed the price of RAM down to $4 for 1GByte of 800mhz DDR3 RAM, so will apple's R&D costs *also* drive down the cost of parts for the rest of us who are happy to sell in much higher volume, quietly, to the rest of the world market including China which is 10x the size of the rest of the world's markets PUT TOGETHER and nobody knows it even exists.
summary: the strategy we've pursued immediately pays off, and the EOMA-68 standard's designed around a different market focus which i believe is sound for at least the next decade. we could always develop new standards that take advantage of the latest-and-greatest innovations, but they would be limited to the latest-and-greatest products. we're going after the bigger volumes - the cash cow markets - and helping the Factories to stabilise their products, take advantage of the latest-and-greatest as it filters down.
does that make sense?