One of the big selling points that these news articles forget is that the RPi foundation have stated that the hardware will be around for a long time. All well and good stuffing a nice chip with a load of IO, but if you're only going to make 10,000 of them and then stop it will get forgotten very quickly.
Apart from some bug fixes on the board the RPi will stay the same and will be around as longs as they can make it. There will also be a lot of them about, last time I checked they had shipped over 200,000 of them!
The Spectrum was not the best hardware, but being cheep and having a large user based made it a success.