there isn't a strict limit, its just not a viable use case for current browsers.
Maybe what we need is Chrome/FF to consider the very high tab count as a use case and handle it better, when you have so many tabs it's not easy to find the 1 in 100 that you're looking for, we would need a new find tool, possible the browser should build a client side tf/idf index and make the whole working set (workspace) searchable. You see what I mean? Until the browser changes to support this usecase, the usage will be klunky and fraught with problems.