You are partly right, but majorly wrong
MoD does not mean just purchasing weapons, but also balancing the budget for the three services this includes salaries, pensions etc.
One easy way to purchase more planes is just cancel pensions.. we can pay for any plane outright, But that does not work
Flying a plane, Ensuring maintenance of supply chain, and ensuring proper procurement and the supplies and paying salaries etc are very much different jobs, A combat guy cannot do that, they are not educated for it A classic example, we purchased Su-30 MKI and we had lack of spares, It took a CIVILIAN DM Parrikar to identify the problem and solve it, Why was the entire "professional" IAF not able to manage it? Maybe they are too stupid to understand it? Maybe they are. but giving benefit to them I might say that they are not trained or educated for this. They are trained to fight, but spare management and supply management is not their forte, but Parrikar being an Administrator, sees the situation much different than IAF. Where IAF saw that as problems of Su-30 MKI, Parrikar rightly identified the problem being of the ordering process and supply chain and corrected it, and we are now reaping the benefits.
So, having a military guy is good if taking military decision, but many times its important to create the right environment for getting the diplomatic situation in our favour so that when we conduct the operation, we are justified in doing so and without any diplomatic outcry (talk of Surgical strike) So it needs to have both Military and diplomatic components . It is not about hitting the enemy, but hitting in such a way that everyone blames them, not us and we are justified for hitting them
We need military educated to take the MoD seat. And we need a Joint Chiefs so procurement can be streamlined.
If these two things happen, the bureaucracy can't do anything.