Because for many people it doesn't immediately matter what is the root cause of their current misery. They are too busy accessing additional support, financial advice, food banks etc.
For others it is blatantly obvious that the current recession is, like covid, a global issue and that the effects of Brexit are now pretty much masked, downgraded, by the global situation.
Because, nasty as this particular pill us to swallow, the number of jobs remaining available does illustrate that there is no appetite in the UK for certain kinds of work, no matter what the pay is like. This will, in time, cause a tightening up of access the various benefits, reversing the salary support given by Brown etc, to businesses during the last credit crunch.
Might even get more restrictions on the gig economy.
Basically we need more people to do more work. Companies need to be able to recruit locally. Round here there is a slow change happening, but it is really slow.
But Brexit is no longer the biggest problem the economy has!