It's whether you're punching up or punching down.
If the purpose of Crap Towns is to punch up, speak to power, to point out the failures of Thatcherism, decreased social mobility through a perptuation of failing center-right politics thanks to an overly-powerful media and political class that is divorced from reality, the absurd dominance of PPE graduates within policy making, and on, and on, on... well, it's great satire.
If it's just to point at working class people and go "haha, their streets are dirty and they eat bad food", well... you're punching down, and it's rare that can work as comedy. It's just mean bullying.
So yes, you can write Crap Towns today, but it lands better if you draw the line from Thatcher through Major, Blair, Brown, Cameron, May, Johnson, Truss, Sunak and Starmer, and their acolytes - the PPE mafia on both sides of the House, and point out how their crappy politics has caused all this, not their victims.