Was beer weaker back in the day?

I came across this picture of an old safety poster that was once displayed in pubs. It shows gear stick (something European cars have) and suggests if you're driving home then you should be OK with 4 pints. The other poster shows beer was cheaper then, so I was wondering if beer was weaker back then so you could drink more.

I know it's going to vary from brand to brand but was say a pint of guinness weaker back then or could men handle their beer better back then?
Was beer weaker back in the day?
Was beer weaker back in the day?
Was beer weaker back in the day?
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