One thing I worry about is if the uncertainty around copyright violation cools down activity in open models while raising the price of commercial offerings. Commercial entities can afford devoting resources towards mitigating copyright violations such as eating the cost of maintaining a database of frequently copied code and identifying most likely origin combined with a large semantic database of code snippets.

An open equivalent might be wary of being accused of contributing to copyright violations since in that scenario, there is no way to force people to respect it.