I think it's clear that factoring works if you can build a scalable quantum computer. But:

1. It's a very lonely example.

2. It's not clear how big the market is for "you can break encryption from the past, but not current encryption, because once QCs arrive, everyone will obviously move away from QC-breakable encryption". And I'm not aware of any other reasons why factoring large numbers would be useful beyond breaking encryptions.