The only barriers to them working are engineering challenges which may prove insurmountable, may not. There are not any theoretical considerations that would make them not work.
I highly recommend reading [1] for an overview of the various skeptical viewpoints on quantum computing. Note that, while Aaronson argues most of the initial arguments are trivially wrong, he admits that whether or not error correction is fundamentally impossible is an open question.
We can keep solving the engineering challenges, but the universe might simply not allow us to get a return on investment with every additional qubit.
QC in contrast must exist or else QM is fundamentally wrong - not incomplete, but wrong.