From the website of the King of the Belgians, a pub in Cambridgeshire - the price list in February 1971, I assume this is immediately post decimalisation.
Average annual earnings in the UK in 1971 were about £1200. Today, it's about £25000. So assuming beer prices had gone up in line with that, a pint of bitter today would cost about £2.30 - whereas in fact the average for Cambridgeshire is apparently around £3.30.
Of course this is a gross simplification, lots of other factors have changed, taxation and other living costs will all have varied too in those 44 years, but I think it's still fair to say, even in relative terms, a pint of beer in the pub is more expensive than it used to be.
That's fine in principle - I would love to think that pub owners are actually a bit more comfortably off than they were back then, but the reality is apparently very different, and whilst nearly half a century ago running a pub which was just a pub in the old fashioned sense could make the landlord a decent living, in the modern era pubs seem to be closing in spades, or gradually morphing into bland generic "gastropubs" and relying more on food sales which is, in my opinion, almost as bad. Just the other day I was looking around for villages with a station within an hour or two of London, hoping I might find some charming little unspoilt rural pubs to visit at the weekend. Instead I discovered a depressing slew of banal contemporary interiors, which had stripped out any original charm and smothered it in Farrow and Ball paint, in "pubs" with websites which tediously trotted out the dreary mantra about their "focus on locally sourced seasonal food" as though there was anything novel in that any more, and no mention whatsoever of actual beer. Admittedly I was looking along the Cotswolds line, so I don't know what I expected really.
It confuses, frustrates and saddens me that, apparently, a pub can no longer get by just being a pub.