That's my biggest concern with Twitters future right now. It already does what it does best, why should new and unnecessary features be added, and like you said Jack seems to understand that. The Investors however think otherwise, since unfortunately the tech industry has adopted the unnecessary change for changes sake for the last decade.

I can already see what such a mentality has done to many other sites, and In the end it drives away the core users of the platform. I can already see this in progress with Reddit for example.