Licensing restriction.
If a manufacturer wants to include the various technologies that make these machines possible then they have to comply with the license requirements demanded by the license holders.
Given that the law tends to back vested interest, I dare say that in effect, these limitations are backed by law also.
Oh dear thats not really quite right, I would point out :
1. All free UK tv, standard def and high def is broadcast unencrypted, this applies to terrestrial and satellite.
2. In order to force manufacturers to encrypt recordings AFTER they are received and limit copying they transmit the EPG data in an obscured manner which legally they need to sign up to copy prevention to be able to use the EPG data.
So any kit from big manufacturers and kit from the shop labelled Youview, Freesat* and Freeview* will enforce copy prevention. * In the case of Freesat and Freeview most boxes only prevent HD recordings being copied and allow standard def, the latest boexes seem to be heading towards complete prevention.
However its very, very easy to record standard def and HD broadcasts in ORIGINAL DIGITAL QUALITY by a number of means, including :
1. Using a PC and a TV card, there are many programs that support this.
2. Load hacked firmware onto certain Freeview & Freesat boxes, e.g. Humax ones have been widely hacked.
3. Use a "generic" TV receiver that doesn't have Freeview/Freesat/Youview branding
Using option 2 or 3 you can transfer recordings onto your PC then onto DVD.
Downside with #3 is that (generally) the unit, when you get it, will not be able to use the Freeview/Freesat EPG data. But fact is that the BBC did such a bad job obscuring the EPG data that MANY people have worked out how to decode it.
So personally I have a Youview recorder and I also have a generic satellite recorder that runs software called Enigma 2, I just downloaded a "plugin" that decodes the EPG data onto it. Bit of a pain having two boxes, but a good mix for me. I transfer recordings to my PC and use free software to turn them into mp4 files, I don't bother making DVDs - I have a network disk that I keep all these films on instead, my blu-ray player plays the films straight from the network disk.
From a legal point of view, I have done nothing wrong in any of the above, I sleep safe knowing I did not break any laws or copyright in this, so long as I use the recordings for personal use only. There used to be a 28 day limit on keeping recordings, I understand that the current legislation does not have any specific time restriction.
Added advantage - films can be played on all PCs, tablets, phones in the house and can be transferred onto these devices for offline viewing e.g. on a train to work. Its all legal, the film has been openly transmitted to the whole country and legally recorded.
See this forum
http://www.avforums.com/forums/satellite-tv/ for info on such satellite recorders, there are terrestrial TV equivalents, but they are more rare.