Have we hit the limit on how fast cars can go?

10 years ago the quickest racing cars ever created by the human race (2004 f1 cars) were -blam!- every track record they went to, however since then F1 (and lmp1) have stalled or even gotten slower, I mean sure a few red bulls set one or two track records but that was with ultra sticky slicks. And whenever F1 cars find speed the Fia cuts them back (same with lmp1), so have we hit the limit on how fast racing cars will ever go with efficacy now taking the leading road?