^ I'm going to go off on a rambly tangent, but I always notice traces of this type of attitude and I always completely disagree with it. To me, it's similar to the "you'll enjoy it more if you lower your expectations" thing.
Sure, having awful sequels doesn't actively take away from the existing value that a good movie already has-- nothing can take that away-- but NOT having awful sequels actively improves that value over time for me. Something can feel admirable, pure, and uncompromised in its quality, integrity and sentiment, and that itself has added value that I appreciate. As a result, just by virtue of not preserving that, it puts a ceiling on how something feels over time. You can ignore that a thing was followed up by bad things and appreciate the good thing for what it is, but it's not going to be AS good as if those followups never never existed or became associated with it in the first place. It's the same thing with a musician who sells out his principles. Sure you can just ignore it, and that initial value doesn't disappear, but there's more appreciable and admirable value when someone never sells out that I think would be a shame to ignore (and you can't have it both ways-- either you think it is a factor or isn't).
The "lucky" comment is an off base and annoying way of assuming that it's inherently a more beneficial approach. There's no objective way to know which difference holds more weight-- whether "not letting bad followups hurt good movies" is more enjoyable or "appreciating good movies that aren't hurt by bad followups" is. I see the drawback of having my attitude of course, but I also think the reward outweighs that drawback, personally (which is why I always argue in favor of this).