Gotta agree with samurai here: Master Chief looks bad ass as hell, and that Hellghast mask... That's bad ass as well! Those designs speak volumes about the characters.

And Sackboy is nowhere near bad ass; not in appearence nor in name. The name kinda sounds like "Scrotum Boy"

ALl these answers are very "inside the box".

11.6 million games sold in 5 years, a new IP originating from a developer with only 20 staff. LBP was Huge.

They have an opportunity now to re-imagine and rekindle gamers interest in the franchise on a new platform, taking it to 3D or bringing in some new gameplay concepts could see it become a strong seller once again.

As far as the management of the series goes, I think they did handle it poorly. They saw the huge sales of the first game and the the timing of the sequel was off. LBP Karting wasn't even necessary.

I think it has sold pretty nice, tho very heavy bundling..
Total sales of 5 games:11.58m.

He's a generic ball of bland. You can dress him up however you want but he's still totally devoid of any personality, struggle, or sympathy. what's the point of the lbp games? to collect stuff and build whatever you imagine? i've played so many user created levels, it's crazy but at the end of the day, it just felt hollow. enemies where just junk cobbled together. i sympathized with the plants in plants vs. zombies more than lbp. the game is good, don't get me wrong. it just has no soul. if little big planet were a tv show, it would be mindless fluff like teletubbies.

i bought lbp on psp and both main games on ps3.

Perhaps this thread is a great example of the problem. LBP is billed as a platformer yet Nintendo fans seems to absolutely despise the games.

I suppose it comes from the gulf between Nintendo & Sony "platformers". Both companies make attempts at both. But Nintendo platformers tend to be more tightly controlled and about running through complex levels with precise timing. Sony "platformers" tend to keep inspiration from the 5th gen design of collect a lot of stuff; talk to a lot of weird and interesting side characters and have plenty of variety from mini-games.

Myself, I much prefer the latter. It's why my tastes evolved from Spyro -> Jak/Ratchet/Sly, and then later again into LittleBigPlanet/Tearaway. It's why I like the LEGO games. It's why I didn't particularly like Rayman Origins or NSMBWii, I suppose.

Also, LittleBigPlanet doesn't have the nostalgia factor that is a big point in Mario selling so well; so sales comparatively should be closer to Rayman (which does have a slight nostalgia factor but clearly isn't enough). Both excellently well reviewed; mostly well received games that struggled to find the same place in the market Mario has. Though, to be fair, I think LBP has done an excellent job to have two 3m+ selling games and two well-received handheld spinoffs that will undoubtedly keep selling over time.

well explained.

part of the problem is that it's aimed at an audience non existing on the playstation platform: women.. sony really need to work on that

I think we're getting off topic here. The OP's question is, why didn't sackboy gain enough popularity to be a big time Mascot like Mario for Nintendo, Sonic for Sega and 'Chief for Microsoft.

Some response says LBP did great and it did very well for a new IP. But let's go back to the main topic, which is why isn't Sackboy a household name like Mario, Sonic or 'Chief? This thread has several interesting answers that are on-topic.
1. Because he has no personality.
2. Because aesthetically, before even playing the game or seeing a video of him, his character looks like a crappy toy.
3. Too bland, there is nothing interesting about the character.
4. You need to play the game before you become interested in him, outsiders think he's "Just a character" nothing special.

The character design focused way too much on making him the "base toy" or the template for all the potentially awesome toy you can build. Thus they stripped away all character specific identifiers, like voice (not even a recognizable whimper), color and even movement (he just lumbers around like a marionette). In order to be memorable, he needs to be an interesting character even before you see him move.

Take a look at various media before looking back at games, the successful characters in films, TV, comics, and others are never generic. They have this quirk, something different that when you see it you'll shit bricks and never forget them anymore. Alas the unfortunately named Sackboy was not well endowed in that department and was thus ignored by the general public.

There you go, hope that satisfies. ;)

He is my mascot! sort of :p
Sackboy kratos, I carry him with me every day! :D