Here is the problem with destroying sequels: Sequels are generally a low risk/moderate reward ratio. If everyone in the industry had to actually think, there would be a lot more gaming companies out of business; something they do not want (quite the opposite, really). Creating original, or innovative, games can absolutely make or break a company.
Frankly I'm partially surprised and relieved that Yahtzee thinks "so be it" to this issue. I agree that banning sequels would force gaming companies to actually think about what they are making but then again Half-life 2 was absolutely dynamic. Losing out to such a game would be a blow to the industry.
The thing is, with sequels, they are "intended" to improve on the game that they previously created. Yet most of the time we get games like Fear 2 here that end up like the Jason films, as Yahtzee so eloquently put it. It's called mainstream media and it's directly involved with the common man like you and me. As long as the common man picks up these games, mediocre gaming media will always exist.
In order to move away from these mainstream ideas, we need to be more critical of the games we play. We cannot simply say, "This game is a 4 out of 5." Instead, we need to point out the good AND the bad and focus less on, "well is it good or not?" The idea of, if something is good or not, is completely subjective. This is what Yahtzee tries to emphasize in his videos yet we still get people, even on this very thread, who say, "well did he like it, what was his score?"