Modular is mainly focused on improving AI related workflows as its business model. That market is easily many $billions, and I think most expect the AI industry to experience explosive growth.
Kotlin is similar to Swift but arguably compiles much faster despite a suboptimal initial architecture, and avoids weird language/compiler specific problems never before seen, like expressions that time out whilst compiling.
Graal is similar to LLVM but can compile a far larger range of languages, is actually used for both JIT and AOT compilation (does anyone use llvm jit in prod?), and has many innovations LLVM never could have even tried to have.
So it's not really clear that he's the best compiler person in the world. More like, the people doing the other stuff aren't in California so don't get the same level of attention.