The comparison works a little better when you take the whole ecosystem into account: you can pick up Java in a few days, but that doesn't mean you'll understand

The comparison works a little better when you take the whole ecosystem into account: you can pick up Java in a few days, but that doesn't mean you'll understand Java EE configuration files, or know how to animate your Android app. Once you start specialising, you will realise that 24-hour days are very finite. Even then, I don't think the comparison works because programming ecosystems come and go. The rate of change is much faster than in human languages. So whether you specialise or try to be a generalist - you can undo that decision within the next decade.