An old soldiers take: https://www.ted.com/talks/robert_gallimore_why_it_matters_ho... In summary drones make it to easy for the countries like the UK and the US to kill with no risk to their own service men. The missiles are not magic, there will be collateral damage. Solders on the ground could mitigate this
Reducing the risk to your own troops is a fundamental concern of most armies out there and has been for millennia.
Robot warfare is a logical endpoint of such development. I cannot see anyone opting out of this race and remaining militarily relevant.