To extinguish, you introduce incompatibilities to make the life of people outside your inner ecosystem (compared to the greater, standard-compliant ecosystem) harder. But since TypeScript compiles to JavaScript and interfaces with plain JavaScript wells, there is really no "extinguish" part here.

Also, the EEE accusation doesn't really apply to open source projects. EEE is bad since after the proprietary product supersedes ("extinguishes") an open product, the community loses control forever. However when an open product supersedes another, the community always have the choice of forking the project to take back control.