It doesn't take a whole population to grind the process to a halt - just a legislator or two, and not passing legislation is just as important to some voters as passing legislation is to others.
It only takes a legislator or two because of the policies and procedures the other legislators agree to. They are free at any time to change their rules of procedure. A filibuster without requiring actual filibustering is a process congress agrees to have, not something prescribed for them from on high. Almost their entire process is something they have all agreed to, if congress is easily deadlocked by one or two legislators, it is because congress does not want that to change.