Beer was probably "discovered" when mashed up grains started fermenting wildly. It's definitely not difficult to make alcohol if one desires!

I do think something can be said to effort put in vs what you get however - I've enjoyed some very good beer that took a little bit more work than letting some grain lying around ferment. Of course, on the other hand, plenty of beers are brewed in Belgium using essentially that method, so it all comes down to one's taste I suppose.