It ultimately depends at what scale. I think most people to be fair are talking about building a clone of what was present back in the mid 2000s. You could build a twitter clone that could handle a few hundred users in a few weeks with modern tech stacks.
The fact that there are at least 3 twitter clones that are less well put together with a decent amount of users handling in the load proves that it is possible.
The fact that there are at least 3 twitter clones that are less well put together with a decent amount of users handling in the load proves that it is possible.