Why is it so hard to find a lock?

I'm having great difficulty finding the type of front door lock I'm used to...

Because I don't know what the official term for this lock is, let me describe the action of opening the door to you. (Leaving the deadbolt out of the discussion because that's not at issue)

I put my key in, turn the key (the door knob does not turn when I turn the key), then push the door open. The thumbturn on the interior side does NOT change position so the door remains locked... I do NOT have to turn the thumbturn to reengage the lock.

If I want to unlock the door completely, I can turn the thumbturn vertical, turn the interior knob and the thumbturn will pop out making the door complete unlocked.

All of the locks I looked at today at Home Depot, Menard's & True Value will require that I turn the thumbturn to reengage the lock after I enter my house.

Anyone here know what I'm talking about.. cause the Home Depot guy certainly didn't. Is there a term for it? Why can't I find it at any stores?

Thanks for all of your help!