The profit motive drives profit, not development. See: rapid enshittification and exploitation.

The important thing there is ‘how are incentives aligned?’

With a lightbulb factory, both the capitalist and the public wins if they’re making better, cheaper lightbulbs. Because incentives are aligned, both the capitalist and the public wins when they figure out how to improve the factory. Look at the prices of LED bulbs or TVs over the last few decades.

Enshittification is due to the public being the product. The public does worse when the capitalist does better.

The profit motive is fundamentally a mixed bag.