I don't know how successful it was in America, however it stands to reason that as a large electronic toy, it would have been relatively expensive, and hence a relatively low seller compared to a cheaper vehicle like the X-Wing. Even so, it must have been deemed to be enough of a success for Kenner because they were happy to reissue it later in ESB packaging. Regardless of its US sales figures however, what I do know is that in the UK for Star Wars, Palitoy famously made their own versions of many toys to reduce the amount of plastic and electronic components used in them, and hence lower the production cost and (I believe) the RRP / selling price. The Cantina, Land of the Jawas, Droid Factory and most famously of all, the Death Star were all different to their US counterparts in this way, but so were the Land Speeder and X-Wing. All of them used less plastic, and or had fewer moving parts, and or had any electronics present removed, compared to the US versions. To this day, I'm still amazed that the Palitoy Darth Vader's TIE Fighter and Imperial Trooper Transporter retained their electronics (the 'Palitoy' white TIE Fighter was of course simply an imported Kenner version with a Palitoy sticker applied).
All of which is to say that since Palitoy were trying to reduce the amount of plastic and electronics (and hence cost) used at every turn, it's not that surprising that the Sandcrawler never made it over here, since it was the second biggest and most expensive electronic toy made for the first film in the US behind only the much more desirable Millennium Falcon. I imagine Palitoy either didn't think they could alter / cheapen the Sandcrawler sufficiently to make it a viable prospect for decent UK sales, or that it would simply be too expensive to sell well if they left it unchanged. It's also worth noting that even the Millennium Falcon never made it onto UK toy shelves until The Empire Strikes Back came out, again presumably because Palitoy thought it would be too expensive to sell well initially when Star Wars came out. So again, it's no surprise that the Sandcrawler wasn't released in the UK for Star Wars if the Falcon wasn't, and by the time ESB came out and Palitoy were happy enough with sales to be confident about releasing the Falcon, without the Sandcrawler being in the new film, they would presumably once again have been reluctant to release it in ESB packaging, again fearing poor sales (as mentioned above, of course things were different in the US, where even though I don't doubt the Falcon massively outsold the Sandcrawler, sales of the latter were obviously good enough for them to reissue it in ESB packaging).
but also canadian.
