Che cosa significa this has been the main difficulty ever since any of us alive can remember ?

Vedi una traduzione

It's an awkward sentence. It means that 'this' [something mentioned previously or clear from context] has been a 'main difficulty' [a major problem that they have struggled with] for a very long time.

In fact, they have had problems with 'this', for as long as anyone living can remember. Or in other words: this has been a problem for the speaker's whole lifetime. For as long as anyone currently alive can remember. So if you talk to anyone about it, everyone will agree that it's been a problem for a long time, long enough that they can't remember a time before that. It has always been a problem. A less awkward way to say this idea would be: "for as long as anyone can remember, this has been a major problem." or "this has been the biggest problem for us, for as long as anyone can remember."