I am finding that most rotary switches are rated 250mA. Is that sufficient for an input selector switch?
0dBm into 600 Ohms is just over 1mA, -20dB into 10K is about 7 micro-Amps. The problem is not current but contact oxidization/corrosion over time, which is why the contacts need to be gold. Power switches actually require a bit of abuse to remove the oxidization but audio signals have no power to do that, so they fail.