P-RNAV in the UK is coming but oh so slowly. LTMA first. UK PBN Policy document due out later this year.
Yes; I have heard this. I am hoping that if it is delayed some more years everybody will realise it is no longer relevant to any flight and will quietly drop it
Also I don't see the UK CAA allowing IFR GA to be screwed. Other countries might do it without thinking.
The average cost of PRNAV compliance for GA would be at least £10k per aircraft and probably nearer to £20k by the time you do it properly, ensuring avionics interoperability with the new bit of kit you had to put in.