What you call "loopholes" are thankfully a standard part of most justice systems, by design.

It's called parole, sometimes released on licence. First you have to get past the parole board who will assess your suitability for release. The theory is to grant you supervised access back to society to regain your place in society. While on parole there's all sorts of reason you can find yourself back inside. Half or two thirds of sentence is pretty common too.

What America does different is not having post sentence - that's post release and parole - rehabilitation, you are always an ex-felon, even after 50 years law abiding. Other nations find offenders can often reform and regain a place in society, particularly if given a fair chance...