Obviously this always depends on what code you compare it to. I don't think there can be much doubt that a well written performance oriented framework-free implementation is in practice always going to be faster than anything using virtual DOM, as one can update simply the parts that need updating without creating the virtual DOM in the first place.
If you assume programmers who don't know what they are doing it is a very different question. Some people will manage to make a train wreck both with and without a framework. But if we assume that there is a skill level where people will manage to make something useful with a framework, but not without it, or vice versa, then I really do not know which way it swings.
If you assume programmers who don't know what they are doing it is a very different question. Some people will manage to make a train wreck both with and without a framework. But if we assume that there is a skill level where people will manage to make something useful with a framework, but not without it, or vice versa, then I really do not know which way it swings.