Even if XBI "only" recovers back to $91 July 2014 all-time high over next 1-2 years, that's a 70% move up from today. That will be a big enticement for mutual funds et al. to re-enter sector.
And given all the breakthrough innovation on different fronts, 'tis very likely that will happen for biotech sector, unless we have a further global economic collapse and longer-than-usual bear mkt.
So, yes, the current wallowing price of XBI and IBB is oversold, overdone.