The reasonable case for multi-person editing of a document is several people at the max editing the document concurrently.
Having thousands of people doing that is not a real-life scenario.
It's better to protect yourself from extremes like that by disabling editing functionality in that case than try to engineer a system that actually allows thousands of people editing a document concurrently (because it would be very expensive in engineering time and especially testing time).
There's literally no business case to be made for supporting thousands of concurrent edits - no one actually needs that functionality.
The reasonable case for multi-person editing of a document is several people at the max editing the document concurrently.
Having thousands of people doing that is not a real-life scenario.
It's better to protect yourself from extremes like that by disabling editing functionality in that case than try to engineer a system that actually allows thousands of people editing a document concurrently (because it would be very expensive in engineering time and especially testing time).
There's literally no business case to be made for supporting thousands of concurrent edits - no one actually needs that functionality.