Considering the ridiculous amount of great sci fi films around and as a huge sci fi fan, I find this very common stace very odd. Then again, I keep hearing people say this all the time and then you find out they haven't even watched genre staples like Stalker, Solaris, World on a Wire, Metropolis, The Face of Another, Heart of a Dog, Fantastic Planet or Dead Man's Letters. Basically, unless you're completely ignoring everything produced outside Hollywood, there's really no reason to complain about a lack of great sci fi films. I mean... now more than ever especially! Under The Skin, Arrival, Her, Blade Runner 2049, Gravity, Interstellar, Mad Max Fury Road and Ex Machina all came out in the last 5 years. With that many all time greats coming out in such a short time you'd figure sci fi fans would be thrilled, not starved. There's a ton of other good recent features in the genre too like Shin Godzilla, Edge of Tomorrow, Predestination, Annihilation, Looper, The Martian, Upgrade, Snowpiercer, the Apes movies, there's literally a ton of quality recent sci fi flicks!
Again, if you look outside the usual Hollywood circle of interests you'll find even more great stuff. Hard to be a God is a legitimate contender for greatest SciFi film of all time, for example. It's one of the greatest times ever to be a sci fi fan, if anything!