Resident Evil 5 did occur as it does with the Albert Wesker being killed by Chris Redfield being a clone of the original and as such, generally just being a very elaborate means to fake one's death and throw his enemy off his trail once more.
However, Uroboros was lost as a result- as the BSAA disposed of all samples they could obtain of the parasite and the canisters of Uroboros in the volcano died from prolonged heat exposure.

Bioterrorism remains a problem, as men such as Glen Arias and Frederic Downing as well as others still continue to use and sell Umbrella's B.O.Ws.