Yes they are a dying breed, unless you go to a Weatherspoons in which case, most still have at least 3, unless a small pub.
IMO, instead of killing it off, the DOND feature, prolonged the life of them a bit more. It clearly was a massive hit for Bell Fruit and the TV program was extremely well known and a very popular program. Others such as Barcrest even ended up following the formula, because it was clearly by far the most popular feature on an AWP. I know for myself, back in the day, I would definitely play a machine with the DOND feature, rather than one without.
What's killed it are the jackpots getting far too big to make gameplay a secondary thought and FOBTs, why play for £70/£100 when you can play for £500.
I've never ever got the appeal of lo-tech machines without any sort of feature/top board.
Perhaps, we will see a resurgence like with retro gaming, whereby, a company or two, produce some £4-£10 hi tech jackpot machines with old style gameplay. Anything above £10 and you start to lose gameplay. Yes £15 and £25 can have gameplay compared to a £100 machine, but then you start to lose gameplay types such as chase trail games. But the cost and getting pubs etc interesting probably mean no, unless someone is willing to take a big and possibly expensive risk.