Also, if the browser concept was patented, how could someone else innovate over browsers, if theres a need to pay for the privilege of being inventive?

Patents and free software aren't necessarily incompatible. For example Raph Levien provides a royalty-free patent grant to software licensed under the GNU GPL that implements his patents.

http://levien.com/patents.html

Patenting ideas is also an excellent way to prevent someone else from doing what you suggest; the patent-holder merely needs to grant a royalty-free patent license to everyone once they have the patent.

(See Sections 7 and 8 of GPLv2, for an example.)