The OP clearly had a poor experience on this trip and, for sure, deserves some significant compensation for the lack of an entertainment system.
I would agree that Thai have stripped back the quality in their (limited) F offering and i have made the same point myself in reports on another thread. However , I have flown the same route in the last couple of weeks, and on that occasion the food ex LHR was very good, just my luck maybe.
The thing i like about Thai F is the new seat which i find really comfortable. I also fly Emirates from time to time (on different routes, but mainly on the 380) and i agree that the soft service is way ahead of TG, but i do prefer the Thai seat. I find the Emirates one to be less comfortable; possibly because it lacks a solid foot support (ottoman) I have found it tends to sag forward somewhat. I have flown both products a number of times in recent months and i just find that i sleep much better on Thai.

But the key point is , if TG is to retain its loyal premium customers , it needs to start to put some value back into the softer side of its offer. At the moment TG does not have much competition on European destinations, for those who value a direct flight (ie not via ME), and it is the only airline offering F to LHR. A few years ago , a passenger wanting F on a direct flight to LHR had a choice of BA, Qantas or Thai, and in those days i mainly used BA or Qantas. It would be good if they had more competition on their European routes again.

Chris63 makes a great point about Swiss. I have never flown with them but hear good things, so maybe an option for the future, also the connection into LCY works well for me.

A colleague of mine switched to EVA recently (from Thai) and was very happy with the service in Royal Laurel. He rates the food and service well ahead of Thai (incl Thai F) and the seat is also pretty good, way better than Thai J and not far behind Thai F, in his opinion.