Physical qubit scale differently according to the technology used. For ions, for example, they double in around 5 years.
Discussion
Let’s talk about software: Schor’s algorithm, developed in 1994 is able to efficiently factor large integers into their primes, effectively breaking today cryptography.
This is not feasible with classical computing, but a Quantum computer would allow this algorithm to work.
6,653,188 BTC are considered at risk of quantum attack.
The latest version of BIP360 is proposing P2TSH, Pay To Taproot Script Hash, and to move to SegWit v2, to address quantum issues.