I am sorry but the only things that are non-modular are computers like the xbox360 and products of that nature that the companies do not want the user to change/upgrade the computer at nearly all cost. It is ridiculous to state that it is "inevitable" to become non-modular. Scientists have been backing the barriers of nearly every science there is in the past 50 years and as such you can NOT conclude that this is "inevitable" it is more likely that by the time we run into a space problem at the level you are implying (which by the way is ridiculous as other people stated... what graphics card uses 2+ PCI slots LOL) that we will finally figure out how to make the first bio-matter computers. Ie: a computer that has a cpu of nearly jello matter that will process data at most likely at first a slower but much cooler rate than our cpu's that we use at the moment.