This suggest that maybe human minds are able to form ideas at a certain speed, and language has evolved to convey these ideas and not be a bottleneck, but there is no reason to improve language beyond this.

Hm, I’ve always struggled with the other bottleneck - speaking. I tend to slur my words because my brain is forming the thoughts faster than I can speak. I could perhaps speed up my speech to match my brain but I’d sound like a maniac.

Don’t get me started on writing. My letters will often transition halfway into a letter thats 3 words ahead.