Senses of humor—both individually and generationally—are complex and ever-shifting. Throughout our lives, we laugh a little less and gravitate toward humor that is "appropriate," self-enhancing, and marked by incongruity resolution; in the process, we forsake other comedic stylings.
My reply in the comments is below…
Something to consider: Comedy ages incredibly poorly; it's a lot more like fashion than music in that way. So the older version of you may not be laughing because the culture (and comedy) moved on – what's a benign crossing of the line doesn't matter anymore because all the lines have moved.
Interestingly, the comedy that ages best is absurd, like Steve Martin, Mitch Hedberg, or Stephen Wright. We may appreciate the Jon Stewarts of the world but that material ages like milk while absurdity can make for timeless comedy. Lenny Bruce may have been groundbreaking in the moment but it seems mostly unlistenable now.
Also, factor in how much surprise is the key to laughter. Once you know it's coming, you know it's coming. It's why people want bands to play the hits while they want comedians to tell new jokes.
To truly judge all this, you'd need either 1) a time machine or 2) to consume the modern day equivalent of "Scary Movie 3" (or whatever else you thought was funny when you were younger).