Basically you're paying to keep the development of the software up and running, so yes it would be nice to see an update or to once in a while to know that there is progress on making the software better for everyone.
Keeping your OS and other software up to date at all times is esential. If they don't give you free upgrades IF you payed for it. (Giveaways I believe shouldn't count) Then you should be allowed to update for your own security.
NOTE: Even so if you read EULA you DON'T own the software you bought. In order to use you have to still agree by their terms.
I think that to be able to receive free updates is normal for a program that I pay , as long as the license is active (for updates that correct bugs, exploits, add new options, etc...)