I don't think it makes sense.
Creating plant cost $X. If Tesla is developing it for some utility then Tesla gets paid $X*(1+margin) and can pay their costs immediately and put profits into scaling up.
Then if Tesla was to be utility it would have to wait multiple years befory money goes back and can be used for growth.
Tesla has multiple better options to spend cash they have than to seat idly... so they can build and provide service for solar plants but I don't believe they will own any in next decade. They aren't Apple, they have quite limited access to cash.