There had been instances where introverts have learnt to network as they were trying to gain traction for their product or idea. Being introvert should not be a disqualifying criteria for someone from being successful
Indeed; I'm an extremely introverted person, but that's only because people don't actually want to talk business 100% of the time. If that's what we're doing, I am very much extroverted.
I agree growth is possible, and I'd never "disqualify" an introvert. Perhaps a better way to put it is I'd disqualify someone unafraid to network, introvert or otherwise.
Not every engineer is an introvert, and cofounders need to wear multiple hats, so you're better getting a 75% engineer who is more versatile.