TCAS has value for everyone flying at low level
Ejection seats have a far longer track record of saving aircrew lives than TCAS. Does your "civil aircraft" have ejection seats fitted? No?! How can you be so unsafe!
I think you misunderstand what TCAS is. It's just another system which brings another set of information into the cockpit. It's down to the user to make best use of the information provided. TCAS was designed and optimised for the use of large airliners flying within CAS, not for military aircraft flying at low level. Suppose we came face to face in a valley somewhere? Would your TCAS have seen my squawk through the granite?
The flip-side of the benefits of any extra system which brings information into the cockpit is that a part of the crew mental capacity must be given over to processing that information. There is a particular danger with respect to any information which is presented visually - like a TCAS display. Time spend heads-in is time which can't be spent looking out. Lookout is what saves you from almost every threat at low level. Birds don't squawk (well...you know what I mean!), neither do hang gliders, paragliders, unmanned captive balloons, suspended power cables, infra-red guided missiles or enemy aircraft.
As I said in my previous post, TCAS has potential value which merits investigation. But it's not the right system for everybody!As always; lookout. He who sees, avoids!