You are correct.
However:
1) If your soundcard supports, say, 24/96 recording but your software only supports 16/44.1, then your quality will suffer due to the software.
2) If you're using software DSP then 100% of your sound quality is dependent upon software. Ever multitracking software does some sort of manipulation even if you're just adjusting volumes and panning.
Your soundcard is just a glorified AD converter really. So yes it'll have a big impact on your sound...but don't assume that software won't have an effect to!
Slackmaster 2000