2: Before Comcast can buy them, someone would need to sell it. It's not clear why they'd want to sell to Comcast.
3: If they did sell, they then (by definition) have the value of a community-wide network in their pockets. They could use that to build another community-wide network to compete with Comcast (then Comcast could buy that, but...)
But more fundamentally, if Comcast had a lot of money lying around for stuff like this, they could just invest it in becoming a properly good ISP that people would actually want to be customers of.
From Comcast's perspective, it's probably easier to invest in buying a company that already exists, than to invest in building something that may or may not work. The existing company already has financials that can be evaluated, rather than estimates that may not hold once the risk is taken.
The form of investment is irrelevant, and yes, that would be a very reasonable way to invest in getting a quality network. They just don't seem all that interested in making that investment in the first place. When you buy an asset, it's not like you're not paying for the risk of building it in the first place, the risk is just firmly priced into the value of the asset.
1: A coop generally can't have outside ownership.
2: Before Comcast can buy them, someone would need to sell it. It's not clear why they'd want to sell to Comcast.
3: If they did sell, they then (by definition) have the value of a community-wide network in their pockets. They could use that to build another community-wide network to compete with Comcast (then Comcast could buy that, but...)
But more fundamentally, if Comcast had a lot of money lying around for stuff like this, they could just invest it in becoming a properly good ISP that people would actually want to be customers of.