I actually saw a fair bit of Pulse advertisement but it was online only-- various wallpapers at IGN and stuff.

Pulse certainly deserved more help out of the gate but at the same time, I would guess that it was destined to fail because (1) Wipeout has a relatively small established fan base; (2) Wipeout Pure had released just two years prior, had excellent sales, saturated the market and was available for cheap at the time that Pulse released; and (3) the PSP user base is not that hardcore (and prone to pirating what they want anyway).

I think that Wipeout HD has the potential to do substantially better than Pulse because it's the first home console version of the franchise in a long while, and because it's digitally distributed and therefore should "have legs" and maintain sales into the coming years (as others have said). As happy as I am that Pulse was released, from a sales perspective, it is perhaps unfortunate that Studio Liverpool didn't focus on Wipeout HD as a launch title for PS3, or at least, a very early release on the PSN. No doubt early release helped Pure achieve the sales it did on the PSP.

Edit-- another STUPID thing that hurt Pulse was that it was essentially a stealth release. This is not how you build hype for a product!