I would say the bigger the repo becomes (in terms of # of collaborators) the more important trunk based becomes regardless of SCM choice. Mainly because merging many branches for many teams becomes very tedious and hairy. By the time you resolve all the merge conflicts, someone else will commit a merge and you'll have to resolve conflicts all over again.
Wouldn't you have the same problem with trunk though? If you commit at the same time as someone else, and they push their changes first, then you'll have to resolve any conflicts before you push.
It seems that trunk based development is merely a means of enforcing extremely short lived "branches".
