The profit motive drives a very short-term hyper-growth mentality, and the decisions reflect that nature (abrupt axing of free service tier or price hikes to show "revenue growth", engaging in questionable accounting practices, etc), which increases success if you define success as cashing out.
If you define success in terms of longevity, given that certain practices essential for long-term survival run counter to the goal of fast growth and high valuations, the profit motive decreases chances of success.
Agreed. I think it works that way because if profit is your motive you will run your start-up focusing on the wrong goal, which is to increase your bank account instead of to increase your users satisfaction or the quality of your product. By focusing on a second order goal you will likely lose track of what really matters. But if you focus on what does really matter your second order goal will be achieved as a by-product.
I do believe that you can achieve higher profits by tweaking an existing, successful model. But to achieve high profits by going for the money directly only works well for those that are either in finance or direct derivatives of finance (such as bank robbers, who after all have the most direct line between 'profits' and their actions ;) ).
If you define success in terms of longevity, given that certain practices essential for long-term survival run counter to the goal of fast growth and high valuations, the profit motive decreases chances of success.