Depends on what you call the “bubble.”
If bike price, then yes, you no longer have to pay north of £1k for a fatbike worth buying. Between them, Halfords and Go Outdoors undercut PX with worthy starter steeds, which further undermined Surly’s price point of ~£1.5k+.
It’s quite telling that PX now only seem to stock the Bluto equipped Fatty Trail.
However, the price bubble has still not burst for decent quality fatbike tyres, I’ve seen nothing close to my Easter Ebay bargain of £80 for a pair of 4.0 Jumbo Jims. I’ve yet to buy a pair of Floaters for £42, because I think then will drag badly on my tarmac commutes (and I don’t really do enough off-road to justify off-road specific rubber at the mo), while I’ve been tempted to get a pair of Mammoths for £68 a pair I’m hesitant because they apparently don’t roll as well as JJs.
Tyre price was the main reason I bought one of the last pairs of FatNotFat wheels, it opened the door to a whole range of decent tyres at prices that would hurt my wallet far less.