The rape charges were always bogus
That is why the Swedish prosecutor refused to interview Assange in London, despite such foreign interviews being quite common. If she did the interview she would either have to put up a detailed charge or shut up.
Recall that Assange spent some time in Sweden after the "rapes", and that the initial issue was to get him to do an STD test, which he foolishly delayed in doing. Indeed, one of the "raped" woman put on a "lobster dinner" for him the next day -- not the usual behavior of an intelligent rape victim.
There is no statute of limitations for charges if you are running from the law. The limitations exist from the time of the offense to the time of being charged. Assange was never formally charged, which let the clock run out.
Now, whether this really was a ruse to get Assange to the USA or just feminist incompetence is unclear, and I suspect the latter.
Swedish rape trials are held in secret, and there is no jury but there is "lay" judges which are ex politicians. And Assange has upset Sweden politically. So how a case might turn out is hard to say.
He may be arrogant, but he did do some good work in the early days of Wiki leaks.