In the case where the dealer/manufacturer is offering subsided finance, the cost of the subsidy is baked into the car's sticker price. I'd expect the cash price to be correspondingly lower than the sticker price to a savvy cash buyer.
A lot will depend on the particular make/ model, how popular they are and how the dealership is doing against their quarterly targets. If you're not fussy about a particular make or more so spec, then you will likely find a good deal. If you're after something popular, or a spec that's in lower supply, you may struggle to get much. I also had a salesman walk away when inquiring about what they considered a niche model (larger petrol engine!) if I wasn't offering within hundreds of the sticker price, he had no interest.
It will be very interesting to see what starts to happen in ~2 years time when a lot of the PCP deals come to decision time. I think one of the reasons for their popularity of late has been a significant shortage of good quality 2-3 year old cars at a reasonable price. Look at a few examples in the more popular family / small SUV segments and it's common to see around a 20-25% drop after 2-3 years. With some scrappage or similar deals to be had on the new models, it makes a more compelling case for the new one. Nissan for example are offering 4k, and 6.9% on the PCP deal, or 4% if you don't avail of scrappage. If however in 2 years a lot of these PCP financed cars start coming on the second hand market, then prices will fall with supply, and the new car becomes less compelling again.
People have different tastes and different priorities. If we were to reduce every purchase decision we make into what makes most financial sense, we'd all be living in bedsits, working two jobs, buying second hand clothes, watching small portable TVs, eating the cheapest own-brand food, never taking a holiday, never drinking alcohol, never eating out.....the list goes on. But hey, life's short, a little indulgence feels good every now and then.