You are right about the two audiences having different requirements. Between School Students and Industrial/Professional users are the advanced students, serious hobbyists, and often semi-professional users who are unfortunately rarely catered for generally; the education market doesn't need it so doesn't have what's needed and the cost of using industrial kit is often too high or it is difficult to obtain.
Targeting the whole spectrum, including that middle ground, is IMHO what made Parallax and their Basic Stamps such a success in the USA, and the PICAXE has that potential in the UK and elsewhere.
While primarily targeting the education sector, Rev-Ed have I believe done a good job of catering for those more advanced users, although there will always be some things some users want which aren't there. The introduction of SMD PICAXE's does indicate to me that Rev-Ed are aware that there are users of PICAXE's outside the education sector, so I don't think it is fair to say all but that sector don't count or aren't listened to.
In defence of not adding X-10; it is something which has never caught on in the UK and therefore probably not something which a UK user would see as necessary. On the other hand, adding X-10 support ( and selling X-10 interfaces ) may be just what is needed to give X-10 the push it needs in the UK to become a more established technology.