Well I'm usually the voice of doom round here when talking about his crumbling fanbase but I really think you're exaggerating how bad things are.
The fanbase (London and national) clearly did shrink a lot in the bleak For Britain-supporting era but he is certainly in no worse a position now than the relatively successful UK tour last autumn. He hasn't done or said anything to frighten off anyone since then, and the longer he goes without expressing support for Farage/Waters etc. the more the fanbase will probably gradually recover.
The combined capacity of the London venues he played last October is 7,000 - most but not all of which were sold.
So, another 5,000 tickets in London offered barely two months later was never going to sell out quickly. Yes, he has lost fans since pre 2018 (when he could shift 15-20,000 tickets in London) but things haven't got any worse since October, and will probably continue to pick up slowly, the more time passes since the toxic For Britain era.
So you don't think his latest diatribe has anything wrong in it that would put more people off then? I think you may need to rethink that. He rekindled the whole far right debate by just mentioning that he wasn't far right together with the , putting it politely, inaccuracies regarding Miley, and his outright lie that he has never been political, all completely unwise from a PR perspective.
"relatively successful UK tour" that is a matter of perspective.
You also think he hasn't said anything bad since 2018? You may need to take a closer look at all the posts on his official website since 2018. Posting of Infowars videos, describing diversity as a "dumbing down", the list goes on.....
If you think his fanbase will recover then I think you may be the one exaggerating how good things are.
He has no record label that will go near him, he has lost his management company and has no PR representative and is unable to release an album.
October to March is 5 months apart. That shouldn't be a problem for Morrissey to shift 5000 tickets from a UK population of 68 million. Standing tickets always used to sell out within minutes but there are plenty still available after 6 days.
Your "most but not all of which were sold" point is valid point but not really quantitive. He didn't sell them out and there were whole sections of the Royal Albert Hall that weren't even put on sale. That was only in October and 2 years since any previous London dates. That too should have easily sold out.
I don't think I am exaggerating anything. Just stating the facts. It all depends on the colour of your glasses I guess.