This is already true today; that is, this cost is only paid the first time you compile. It's still not fast enough for people.
On my machine, a fresh build of rustc takes an hour, and small changes take 20 minutes, and even that makes it a giant pain. It's an ergonomic thing, IMO.
A bit influenced by the fact that rustc has to compile itself three times. :P
https://edn.embarcadero.com/article/20803
And even today Delphi 10 is quite fast.
Same applies to many other compiled languages with modules.
And no where near as fun. Hilarity ensued when I didn't realize there was no garbage collector.
Turbo Pascal was more a kind of simplified Ada than a pure Pascal, which made me look down on C when checking down the laundry list of language features of Turbo Pascal 6.0 versus ANSI C89 in 1993.
Also by 1999 no one was doing anything serious in Turbo Pascal with the last version being targeted at Windows 3.1.
Delphi 1.0 was released for Windows 95, and it did at least have some kind of GC for COM based classes.
Also Delphi 10 might not have every Rust feature, but it surely has it own set of complex language features.
Or if you prefer Ada, C#, D are also possible sources of information regarding performance of compilation toolchains, with relatively complex languages.
Now, viewing this as someone coming from Python, Ruby, Node, etc., I can see compilation as being annoying. Is it really the only reason that they are disliking the language or is that just a strawman?
I wonder if too much attention is being paid to this. Now there are legitimate things we can focus on, such as making cached precompiled libraries very easy to use. This can especially be important in CI environments... This would also generally make most compilations fast.