I see this a lot in games that use RNG for loot distribution.

The problem here is not the system but people's understanding of statistics, and how probability isn't a certainty but rather an estimate, influenced by numerous variables (controlled or otherwise).

In a nutshell; the theory of the relative frequency of a probability (%) suggests that the probability (%) of a given event occurring (i.e. your loot dropping) is 'more likely' to occur the the more often said event is attempted.

In Laymens terms; it's random. The more you try the 'more likely' you are to see the event occur but there is by no means a guarantee. As some have pointed out this is why token systems have become the choice of more and more MMO's these days. It's guaranteed i.e. 100% likely you will get your loot.

And really there is nothing SE can do about it.