Why did you say it?
Your whole thrust seemed to be that towed guns are best/self-propelled aren't. I don't agree. We are in an entirely new era and combat systems must be fast, mobile and agile.
The large towed stuff needs to be relegated to the museums where they belong.
I note that you still haven't said anything about your experience in artillery. If you haven't any grounding in the real thing, what good are your opinions on the subject? If you aren't totally broken down. maybe you should sign up and spend a little time learning about this stuff first hand..