I've been following this space for a while and this is a good question, but I think the answer is really a "ranges from 10 years to never".

There's a lot of investment currently in the quantum computer space (+ a lot of hype and scams). Yet this is still all very early research and far away from any practical use. The challenges to really build a QC that can break cryptography are enormous - and it is absolutely a possibility that they're too big to overcome.