1 engine vs 2 engines

Before it was a good case that two engines were vital just incase one would fail, the other would give enough power to make it home.

however nowadays engines have become alot more reliable, more fuel efficient and powerful. Case in point are the F-16 and Mirage 2000 known for ease of maintenance and cheaper to operate, there has not been too many cases of unreliable engines. the JSF is also a one is it now very practical and cheaper to have a single engine aircraft? are the days of dual engine aircraft gone?

for example would it have been better if the MiG-29 used 1 AL-31F instead of two RD-33s? or if the Typhoone and Rafale should use 1 powerful engine in the 35-40,000 lbs thrust range?