Why do we have so little trust these days?

Going through the interview process for a company, and they are simply not releasing the offer because they fear I will look for other opportunities, even after I have clearly stated I don't have any offer in hand, and just want me to reduce the notice period which is a fair demand I feel everyone does it. I get partially we are to blame for this no trust, but there has to be some level of trust, every company has notice period policies.