I agree, although I have never had a performance bottleneck related to std::list that required a move to std::vector. Do you know at what point std::set becomes more optimal (in some dimension) than std::vector?
Edit: Sorry, I read your comment incorrectly. Instead of std::set I would use a sorted vector without thought for anything up a thousand elements or so. After that it's probably worth profiling. Vector is probably still good even quite a good way after that depending on your use case.
Until memory fragments and you can't allocate a contiguous block for a big vector.
Big vectors inherently avoid sub-page fragmentation because they're allocated directly via mmap. The only thing that matters is having unreserved address space, and 64bit gives you a lot.
What you say is true for a worst case load of millions of vectors that are larger than half of the mmap threshold size (typically roughly page size or a small multiple of it). So this might just be a semantic disagreement, but I don't think of millions of 3KB vectors as 'big' vs a smaller number of MB or GB vectors.