No, in this case it is much more pragmatic. Elon has commented on this aspect himself. When he started he thought of just buying rockets and related equipment from Russia on the cheap but quickly found the exuberant prices states want to charge. He then made a first order approximation of how much it’d cost to just manufacture things he needs and it was an order of magnitude lower - thus he bit the bullet and started doing just that. Had the states let him buy things at a fair price may be the controlling of the stack would not have happened.

In my opinion, it's not that he wants to control so much as that his goal is going to Mars.

Someone that goes to work to do the tasks assigned to them (which applies to both managers and those on the line) vs. someone that goes to work because they want something (e.g. maybe a certain product made with certain features) thinks very differently. The latter has a whole plan and the plan has certain sub-requirements that all feed back into the greater goal.

As part of going to Mars, you will likely have to send many supporting missions, which drives the requirement to lower costs. When designing bespoke systems, contracting it out to third party vendors can be expensive. Usually you contract out to third party vendors because they can utilize economies of scale because they have many clients who are asking for the same thing, but there are no economies of scale here because no one has reusable rockets in their catalog.

It's really because SpaceX is Musk's hobby company with the singular goal of putting a colony on Mars. The commercial launches and Starlink are just a way to leverage all the infrastructure they've had to build to make it pay for itself.