There's ambition and there's unrealistic optimism. Look, there's a narrative a lot of SC fans have formed that critics of the project don't understand game development. I disagree. I think early on many critics saw the scope of the game and everything that was being promised and many of us thought "it would take years and years for a game of this scope to get made even if it were coming from an established studio".
Then we get Roberts throwing out wildly optimistic dates for years now that any reasonable person knows they have no chance of hitting. Then when those dates pass, we get people saying "of course it's not ready yet, AAA development takes time". And the critics know that, and the defenders know that, but that doesn't stop Roberts from slapping a 2016 release date on SQ42 or telling you guys you'll have 3.0 by the end of the year despite not even having 2.6 yet with 2017 rapidly approaching. The critics aren't the ones setting unrealistic time frames, CIG and Roberts are.
Most people who call the game a scam aren't saying that there is no game, no progress is being made, and nothing is being worked on. I think most believe that Roberts and CIG vastly overstate progress, show tech demo's of things that aren't even close to working but promise them soon, and do this partly to keep funding strong. Given that AAA development does take a long time and MMO development even longer, the scope of the game that they did have to build up studios, that unexpected delays happen, and that they are more or less working on two games at once, I don't think it would be unreasonable to expect a 2018-2019 date for SQ42 and sometime in the early 2020's for SC (and even then I'd expect some features cut). If CIG were to actually put those dates out there though, it could have a negative impact on funding. The "scam" is that they paint an unrealistic picture of the progress they're making.