Scaling horizontally is significantly cheaper than the additional engineering cost required to build these applications in statically typed languages, especially in developed nations like France.

The real bottleneck lies on the database side, but it is rare for an average organization to actually hit its limits. Don't think at Microsoft scale if you aren't them.

Server costs actually matter quite a bit at the scales of the incumbents in this space. Also, speed can be an important part of UX. Scaling horizontally won’t help if the engine itself is slow enough that there is noticeable lag even with just a single document getting edited by a dozen people.