I think people are overstating the impact of CAMRA. It was the craft ale boom that boosted the popularity of ale as opposed to lagers. CAMRA was around for years when ale was losing popularity.
The chart you show reflects the number of registered brands i.e beer names which reflects the sheer number of different beers brewed by micro breweries. What it does not show is the volume of beer produced which is still declining. https://www.thedrinksbusiness.com/2019/09/summer-beer-sales-in-pubs-have-almost-halved-since-2000/
The other thing that needs to be mentioned is what is craft ale. Some of the biggest sellers of craft are actually big brewers or small outfits that have sold out to big brewers. Revered craft brewers such as Camden, Meantime, Beavertown, Brooklyn have all sold substantial chunks of their business to world wide brewers such as Carlsberg, Asahi, Budweiser etc.
While other top selling craft brands such as Shipyard, Blue Moon, East Coast IPA etc are brewed by large breweries such as Marstons and Coors but labelled as craft. The big brewers have spotted a potential competitor and have moved to grab their chunk and exert their control over it.
I am not knocking craft but like all things it is not as simple as it may seem.