As you say there are clearly no significant boost to the UK economy from Brexit, which is why its cheerleaders are now treating other EU countries' financial woes as some sort of Brexit Bonus - like an embittered divorcee taking grim pleasure in hearing that their ex-missus has lost her job, while he sits alone in a cold, filthy bed-sit.
They also choose to ignore the fact that some EU countries are doing better than us, others worse - thus instantly dispelling the myth that 'being in the EU' is the cause of their problems (just like it wasn't the cause of ours).
Brexit promised much and delivered little, hence its decline in popularity.
With the India deal mired in problems - the main one being India's insistence on relaxing immigration quotas (oh, the dilemma!) - plus the implementation of the long-delayed, but inevitable incoming border controls, with all the costs and shortages that will bring. - these figures are unlikely to improve in favour of Brexit.
As I've said before, we won't rejoin per se but will drift back into some sort of customs union++ sort of arrangement.
A few people will moan from the Opposition benches & Farage will have something to talk about again - but most people will see it as just plain common sense.
