It may be due to the "soon to be demise of analog TV stations transmissions" and are going to HD transmissions...

That TV guide is just another channel supplied by the cable supplier, unless there's some magical thing I don't know about like some sort of wireless thing like the atomic clock thing that connects to clocks and watches? TVs display what's fed into them, nothing more, nothing less except for their internal menus....again, correct me if I'm wrong.

Whilst I'm in Canada I assume the HD/Digital changeover is similar, what they are turning off is analogue tv BROADCASTS ie what you get for free from an aerial, bunny ears, old coathangers etc. If you have a cable or satellite feed, it will continue. I suspect standard def will be available on cable basic (or as an extra output on your cable or satellite box) for a very long time and HD tvs will probably offer it also for 'legacy devices' like old video cameras, vcrs etc.

I would talk to your cable or satellite provider for clarification.

As for set purchase, I'd say although 'natural selection' is phasing out sd sets (either through attrition or by manufacturers no longer offering them) it's a personal/financial choice, a lot of analogue sets are still perfectly good and can be had for a bargain (my big screen purchase has been set back by years, because we were able to purchase a beautiful 28" set from the school where my wife works!)

There are conversion boxes too, that will downconvert hd to sd. Remember also, a lot of 'hd' programming is upconverted sd if it's reruns from sd videotape and even some film will be recycled sd if they were too cheap to re-transfer in hd, and a lot of hd stuff goes through so many boxes on its way to you it may be less than ideal.

MPEG-2 is the compression format HD uses, it's "lossy" which means it loses detail on its first compression. Any further recompression adds to the loss.

OTOH when it's good, it can be really good. YMMV.