This rhetorics is too easy to land when over genre strive with imply people wanting more of teh same.
uhhh... could you rephrase that
Ouch ... this make sense, when I wrote it
but with should be which
Basically just because a genre died, and there is people longing for him, doesn't imply nostalgia, it imply the offer died, offer that still exist for other genre.
My speculation is that genre dies when they hit driven market move to another hit driven genre, genre become hit driven with the presence of "king" game that sustain the impression of demand. If there is enough "king" fighting over the market this effect perpetuate. But if the king dries the market around him the genre become associated to the king and the market collapse (see nintendo games). Or else the market fragment too much to sustain and lead to a arm race that eventually kill the ROI (farmville like). Or the market degenerate without king establishing themselves and a lack of innovation (adventure games until recently, which broke off into many more optimize subgenre).
Talking about nostalgia about a genre is for me nonsense, nostalgia applies to title, a genre may fail to evolve or not, attempt at reviving a genre won't work without going back to the core appeal (which mean the ability to do the right diagnostic) or modernizing the core by successfully addressing the failing or shaking the format.
2d platformer still exist and are popular for a reason, they just don't pull amazing number because they are too varied (fragmentation) and easy to produce, there is also teh presence of a "drying king" by nintendo title who pull amazing number across many series and cover a huge spectrum already.
3D platformer died because kings rapidly got to peak quality (still unmatch to this days) and the high (technical) cost associated with getting it right (camera and control), high level of skill required to pull it off (level design), and a lack of perspective (theming and character appeal had flat lined) which limit ROI.