Fed can serve 130 occasionally. Novak tops out like mid 120 and Nadal maybe low 120s. Nishikori is one of the worst servers in the top100.
You can win with a 120 mph serve but then you better be a top grinder like Nadal, Djokovic or nishikori.
Other more offensive players like thiem, wawrinka, Anderson, cillic, isner serve well over 130. On the other hand Nadal or Djokovic could probably beat most top100 without topping 100 at all but they are exceptions
Let's look at these guys' USO serving speed stats:
Wawrinka:
Avg 1st serve: 114 mph
Avg 2nd serve: 89 mph
Fastest 1st serve: 130 mph
1st serve %: 57.6%
Cilic:
Avg 1st serve: 116 mph
Avg 2nd serve: 92 mph
Fastest 1st serve: 135 mph
1st serve %: 57.2%
Thiem:
Avg 1st serve: 116 mph
Avg 2nd serve: 94 mph
Fastest 1st serve: 137 mph
1st serve %: 56.2%
Anderson:
Avg 1st serve: 125 mph
Avg 2nd serve: 105 mph
Fastest 1st serve: 139 mph
1st serve %: 64.0%
Isner:
Avg 1st serve: 124 mph
Avg 2nd serve: 109 mph
Fastest 1st serve: 141 mph
1st serve %: 68.5%
And just because you can crank 130-140 mph, it doesn't mean you are doing it regularly. Unless you are 6'8" or 6'10" like Anderson and Isner, you probably aren't going to make a lot them in at that speed anyway.
Look at the low percentages for Thiem and Wawrinka. Nadal and Djoko may serve 5-6 mph slower on average, but they are also making them in almost 10% more often (65% in for both of them)