It is worth mentioning that apart from Australia noone bought the F111 either. The market for theatre nuclear strike aircraft is limited. The F15 Strike Eagle (a US Tornado or UKVG) has been much more successful.
The US could afford long and medium range nuclear strike aircraft in some numbers. Only the Soviet Union could try to do the same.
Polaris blurred the role of the medium bomber in NATO. It made US B47s and USN Vigilantes in Europe unnrcessary as well as RAF V bombers.
The 50 machines for SACEUR were eventually replaced in the post Cold War UK by low yield warheads for Trident.
I’m not saying you are wrong but the “medium bomber” role for the US, plus numbers deployed to Euro, was tied up with far more than the fielding of Polaris.
In practice SACs theatre based B-47s were primarily replaced by US based B-52s (with their longer range and expanded tanker support they weren’t nearly as dependent on local basing). Additionally in the 60’s the US ICBM force massively expanded, plus the US Polaris sub fleet also expanded, again all impacting the role and focus of the US’s nuclear armed bombers and strike aircraft.
Hence while it’s also true that US nuclear armed tactical fighters and strike aircraft were in this period getting larger and longer ranged in this period (leading to the F-111) to somewhat converge with theatre bombers it’s probably mistaken to see them as direct replacements for B-47s.
It’s more that the tactical fighter-bomber (F-105, say) converged with the tactical bomber (B-57, say) and that with the miniaturisation of nuclear weapons they converged with the medium strategic bomber (say, B-47). Something similar seen with UK and UK-multi-national aircraft.
The F-111 was a tactical strike aircraft evolving into a theatre bomber primarily operated by TAC, the B-47 was a medium bomber that evolved into a strategic bomber that was almost exclusively operated by SAC. The B-47 was primarily a strategic system primarily replaced by other strategic systems (US based B-52s, US based ICBMs, sub based Polaris missiles).
The FB-111 variant is a bit of an outlier (essentially a tactical bomber tasked with a strategic role?).
And I haven’t even gone into the complications of US and NATO land based nuclear tipped medium range missiles of this period and their impact re: nuclear armed strike aircraft.
There may well be similarities with the V-bombers and B-47 in that late in their careers they were given more theatre rather than strategic focused roles and target listings as a byproduct of “loosing” their strategic roles to other systems. However NATO tasked Lakenheath based F-111s were very much TAC birds and not SAC FB-111s with their different targeting priorities etc.
The TSR2 evolved in a direction of getting closer to being a theatre bomber but was never intended to be the pinnacle of the UKs nuclear deterrent (which was supposed to be V-bomber then V-bomber armed with Skybolt and ended up being Polaris armed SSBNs). The fact that the last Vulcans ended up in a tactical role, and that the TSR2 at various stages was considered for somewhat improvised interim quasi-strategic roles (for example as a gap filler after Skybolt cancelation) does cause confusion, potentially including some in the RAF and governmental/ political levels. But the TSR2 wasn’t ever really intended to replace the V-bombers and it’s the Vulcan that ended up being a partial interim replacement for the TSR2. And UK Polaris (or Trident) subs didn’t really replace the TSR2 (or those last NATO/ tactical tasked Vulcans); it was a whole series and combinations of various aircraft that did.