The real problem is that the main providers have not yet managed to productively incorporate Computer-Based-Teaching (CBT) or, as it is often now called, Computer Aided Instruction (CAI) into their offerings. Thus, even with Open University material, what you typically get is large chunks of text which could be in any textbook (though in fact, in the case of the Open University, it is especially developed so that it is focused on the specific job in hand - which makes the education content more powerful). Between these slabs of text activities are inserted, which the students complete, to consolidate what they just learnt.
It now increasingly uses PC-based systems to also allow them to test themselves, usually on the basis of multiple choice questions, to see how much they know. It then provides a degree of feedback; explaining whether they are right or wrong and, if wrong, what the real answer was. Truly effective Computer-Aided-Instruction comes, though, when this feedback is used to manage the progress of the student. Thus, in theory at least, depending upon how well they have learned the lesson you may allow them to skip the next unit - because they already understand enough. Perhaps more likely, they may have learned it so badly that you have to return them to the beginning of the previous section. This all about managing the student's individual progress.
Some software for doing this is available, in crude form, but as yet it needs to be significantly enhanced. More important - and this is a killer - you have to put very much more effort into developing the material content it uses - typically providing at least three times as much (where you have to cater for all the alternative answers!) and in particular the interactions with the management system. This is where most systems currently are held up. CAI is not a cost-free solution!
Forecasts have suggested that the organizations who should find it easiest to get round problems - and produce the most popular education programs using technology very similar to that now available in the games market - would either be the IT multinationals (especially Microsoft) or the Hollywood studios. The logistics of it are very much like making a movie - and in fact the most expensive part is indeed making the moving pictures which illustrate the program. In fact, this does not appear to have happened yet.