If a service does not have like 10 million users and 10K+ QPS, the choice of language can hardly be the bottleneck. The choice of database is usually more influential on performance.
https://misskey.io is one of good example out here. Backend is written entirely in TypeScript and could withstand with many online users.
Discussion
Because it’s very easy to horizontally scale a stateless backend service and very hard to horizontally scale a database to a cluster.