I do all my "fun" computing these days on a BBC Micro, in assembly language. I don't have total understanding of the ICs, it's true. But in its 64k of addressable memory (32k RAM), I've a pretty good idea of where everything is and what happens when. Very satisfying.
I was the proud owner of an ARM copro [1] many years ago (I still have the Master it was plugged into) and the first Acorn RISC machine (an A310 with 512k RAM if I remember correctly).
They were and still are extremely powerful and productive machines.
We really are building things with too deep abstraction hierarchies causing knowledge to be divided
Abstraction is necessary, true, but it's not clear to me what the abstraction-level we have now really gets us. In other words, say we had a BBC micro with a 2Ghz 6502 in it. What productive computing tasks that we do now could it not do? Or let's imagine an Atari ST with a 2Ghz 68000, to get us a little more memory. What could it not do, that we need to do now? I'm struggling to think of anything.
It doesn't get us anything at all other than a fucking huge rabbit hole to stare down every time you do anything. Lets look at a pretty naff case for .Net CLR on x86 for windows workflow:
application -> xaml -> framework -> server -> container -> c# -> cil -> bytecode -> x86 instructions -> microcode.
Now forth on a 68000:
Forth screen -> 68k instructions
To be honest, for what I consider to be life and death stuff, a 10MHz 68000 is good enough (I have one in my TI92 calculator).
The main thing is that you'd need a new set of abstractions for security, and then you'd need to implement HTML5 on it anyways to do all the things we can do on a computer now.
Such as what? 99% of websites are a) screens where you enter something into predefined fields, to be stored in a database and/or b) screens that format nicely for display things that you or other people have previously entered. They were doing that in the 1970s. Only the buzzwords change.
If you're in the UK, there's a liquid market in BBCs, C64s and similar on eBay. There are a few sellers who refurb them (e.g. new power supplies, cleaned up cases etc). You can easily adapt a BBC to use SCART too (the lead will cost about a fiver) and use it on a modern TV, if you don't fancy using a big old CUB monitor.
I hope that the RasberryPi will be a re-run of the BBC Micro, they could do a lot worse than bundle it with a modern version of BBC basic, which was very advanced for its time.
I (the parent of your post) actually have a BBC Master (and the advanced reference manuals) lying around still for precisely that reason. It's quite a handy and very powerful little machine to be honest.