We both realize that not every infraction draws a flag.
The purpose of imposing penalties is to discourage violating the rules. If the burden of the penalties does not, in fact, discourage violating the rules, then eventually every team will modify its behavior and we will be looking at a totally different sport.
If that's an undesirable outcome, then some changes will need to be made so that penalties do discourage CHEATING.
That’s the nature of sport though. Teams find loopholes, rules committees close them, teams find new loopholes... I expect if more teams start following the Seahawks model the NFL will probably adopt something similar to the NBA, where the punishment for penalties begins to ramp up as the team gets more flags. If starting with your 5th team penalty of the day there was an extra 1yd * total penalties (ie 5 for the 5th, 6 for the 6th) this method would become a lot less attractive. Having offsides be 11 yards and a probable first down would be a definite tactic changer.