Right, except Fabregas also sometimes starts ahead of those guys and he's not a striker at all. VdB's approach to many things is rather unusual so its hard to draw serious conclusions about how much quality Torres might have retained as a forward. Del Bosque seems to be a lot more concerned about backroom politics and mantaining group coherence then most managers, which is why (well-liked) Reina is always in the squad even though logically you would take younger 3rd goalkeeper so they can smell big tournament.
Fabregas starts ahead of those guys sometimes because he's essentially a forward anyway now. But that's irrelevant; Fabregas plays very well as a striker, so it's unsurprising that he occasionally plays there, and moreover it's not a slight on Torres given that Fabregas excels as a striker for Spain. If Del Bosque was playing Fabregas there and he'd never even played as a striker before AND was terrible AND he kept on getting started there, then perhaps you'd have a point. As it is, Fabregas - a better player than Torres - occasionally being played ahead of Torres in a position he's very familiar with and performs very well in (in a different style of role as well) is entirely fair.
You're right about Del Bosque's team building policy, but it's been repeated so often now it's gotten to the point where people assume he'd just leave out quality players in favour of worse ones just because of that, which isn't the case at all. Taking Pepe Reina, a third choice keeper whose only job is pretty much to maintain squad harmony, is a whole world away from taking a striker who could reasonably be expected to start. This is especially true when you consider that Spain are already taking a young keeper in De Gea.
Frankly, who in the Spain squad can we reasonably say only got in because of Del Bosque not wanting to leave any 'squad harmony' guys out? Raul Albiol, maybe, but he's a very experienced defender in his prime who's had an excellent season for Napoli. David Villa, perhaps, but he's a **** of a player for the big occasion and has a fantastic international strike rate, as well as being able to play anywhere in the front three or even just behind. Apart from that, the only other possibility is Torres, and if we're using just him as an example of Del Bosque taking players on squad harmony basis rather than quality, then it's a pretty shaky argument, especially when you consider he left out stalwarts like Arbeloa, Jesus Navas, Llorente and Negredo.
I don't buy the argument that Del Bosque would sacrifice quality for harmony one bit, not in regards to Torres. The reason he's going is because he plays well for Spain, fulfils an important role that Spain benefit from better than the alternatives (Llorente isn't mobile enough and doesn't dribble like Torres, Soldado's had a truly terrible season and is only a goal poacher anyway, Aduriz never seems to get a chance at international level and is even older than Villa, which by your book apparently makes him incapable of doing anything other than falling asleep and ******** himself) with the possible exception of Negredo, who I'm a big fan of and is multitalented. I suppose the major reason for not taking Negredo is that his second half of the season was very poor, and that he's probably a bit too similar to Diego Costa, who is a superior player.
Then again, I'm pretty sure players who are about to enter peak of their career, don't decide to become pensioners in MLS.
That counts for absolutely nothing towards their quality. Players like Rafael Marquez have gone to the MLS and been **** because they've declined massively, whereas you get others like Henry, Dempsey, Cahill and so on that have excelled because they're still good players.