Imagine having hundreds of languages with only trivial difference in syntax. Consider the fragmentation and effort wasted on re-inventing the same low level libraries again and again (here is the hundredth version of unit test library). Sure, only language would be bad but so is too many.
A language doesn't gain traction cause of syntax or anything like that. It gains traction because a platform developer promotes it.
C# and Java had what amounted to trivial differences, when they started.
Kotlin and Swift also aren't very far apart, both in terms of syntax and power (in Blub power continuum terms).
There's very Computer Science-y reasons for these languages to exist as separate languages, but they do cause of product differentiation and platform lock-in efforts.
I doubt language innovation would happen with that setup.