It's certainly true that pub numbers have declined according to statistics from the British Beer and Pub associate, but I wonder how they work this out. Once upon a time it was easy to tell between a pub, a restaurant and a cafe. Now, nothing like as easy.
So one of the best restaurants in my city (tables all booked 6 weeks in advance), also has a sizeable bar at the front. Some people treat it as a restaurant, some as a pub, just going there to drink. Also on my way to work through London I occasionally stop at a cafe, which is also a bike repair shop - but also sells beer and wine etc and is a convivial pub atmosphere in the evening.
And despite the reduction in numbers, in many ways we are currently in a golden era for pubs. Think about the 1970s, when CAMRA (headquarters just down the road from me) was set up. Sure there were loads of pubs but also a massive degree of homogeneity - most were run by a small number of breweries, sold a limited variety of poor quality mass produced beer and the range of other drinks was very limited. Today the choice is massive - there is the sell it cheap, every one is the same Weatherspoons - but also loads of one off pubs and bars selling a huge variety of often changing beer. Many, of course, are now microbreweries, so you can try beer actually made on the premises. The variety of other drinks has changed beyond recognition, with many having extensive lists of wine by the glass, plus others specialising in a bewildering array of whisky or gin.