I have an English uncle who grew up around the time lager became the go to beer in England. He drinks a variety of beers these days including ales and lagers, but when he was young only drank lager.

Many years ago I asked him why he switched to drinking larger when he was younger, and his answer boiled down to consistentcy/quality.

Ale in England is pumped by hand into a pint glass, with a quaintly named beer engine, from a cask (not keg). The casks are open, so each unit of beer extracted is replaced in the cask with air. This means many opportunities for infection and oxidation of the beer so it goes off very quickly, and the lines between the cask and the engine need frequent cleaning.

This is expensive and time consuming, so bad pubs often push it as long as they can before doing it, or often just let it go bad. I've been to one pub where I tried every ale and they were all off.

Back when my uncle was drinking in the 60s and 70s he found this very common, so ordering a pint of ale often meant you might get a bad beer.

Lager is in a keg which is CO2 pressurised, so any larger removed is replaced with CO2 this helps keep it drinkable for much longer. The CO2 overpressure is what forces it out of the keg, so it's served from a tap not an engine.

Ale isn't pressurised with CO2 as it has low carbonation, so using pressure to force it out would also carbonate it further and change the product. So that can't be used to extend its life. You can get a soft spile to put in the literal hole in the top of a cask, that keeps flies out, but still air flows in. There are devices called cask breathers that would replace the beer removed with a blanket of atmospheric pressure CO2 so no further carbonation, but much improved life of the beer. CAMRA in the UK fought hard against these as they claim ale needs some O2 to mature (maybe breathing like a wine). I think they fought too hard, harming ale sellers and drinkers. I don't know what their contemporary opinion on them are.