My response to that question these days is: have you actually watched porn? Not fapped to it. Sat down and watched it. Yeah, there's a part that does what it is supposed to do, but it's wrapped around some of the worst production values out there. Porn flourishes on the naughtiness of it, to the point a lot ignores titillation and seduction value. We either jump right into the sex, or run though some half assed script with acting only slightly better than the audio (seriously, if I have hear every moan during the act, why can't I make you what they're saying first) or some sketch like a bad Saturday Night Live sketch (or in other words, a normal SNL sketch).
Going elsewhere, I guess it depends on the game or anime (or movie or comic on occasion). Something like Senran Kagura is a bit titillating, but it's also bright, colorful, and often funnier and more entertaining than just watching 2 people (or more) fuck. Something like Moe Chronicle (a dungeon crawler where you catch monster girls for your party like pokemon) is again, colorful and the girls' designed are creative and unique. It isn't fap material, but something meant to look bright and exotic, rather than plate armor or normal clothes. Sometimes it isn't the titillation, but the circumstance, like the humor in any harem anime with a girl not sexually repressed or shy around others that want her to cover up, or an exaggerated realism in Queen's blade that battle damage can and will expose the naughty bits.
Then there's DOAX3 and similar games, that, can truly be counted in that ecchi / porn area, but it offers something porn doesn't: control. In porn or photo shoots, I'm an observer on a passive ride, while in a game I can look at the parts I want when I want to, instead of enjoying a view one minute, and moving to something I don't the next, on top of choosing the girl and activity. There's so much in movies you just have to accept, which may be why I think we've all seena bit of porn that didn't do it for us, but the idea of a game opens a lot of possibilities.
Honestly, I think the question gets asked by people that are more sex-negative than they want to admit to themselves, and the firm line between titillation and "normal" entertainment must be there and very clear so that they can feel sex-positive without having to face a more sex positive (and less repressed) world. They can shuffle the porn off to the side and ignore it, but let it be high profile and/or with everything else, and they go nuts.