No, it still isn't true. Consider things like a web browser. Huge codebases where damn near the entire thing is "hot." Or OS's like iOS and Android - again, huge codebases where everything is "hot" (everything is either impacting responsiveness or battery life, after all), and vanishingly few if any "super hot tight loops." Same again with game engines like Unreal. It does have data processing hot loops like physics simulations, but it also has audio paths, rendering, AI, etc... that are also all still very much hot. Even the code that does loading, a "rare" event, is still hot because the user is blocked on it.

The "hot data processing loop" definitely exists in some systems, notably those that really just do one single thing, but those are also far from even the majority case. At least not on anything where the end user is directly paying the computational bill (aka, very few client apps fit the "single hot loop" profile)

But if you go pitch Apple with a "hey, we want iOS to be 20-30% slower because some people are uncomfortable with narrow contracts" they would rightly laugh you right out of the room.