Official 
post (which disavows Roger Craig Smith)
Seriously why. Sonic and the Black Knight was the last one and it was also the last time you could beat the final boss to a kickaas buttrock theme song. Why don't we have this anymore?
Different generations of 30something. The 30somethings now want them back; the people who were 30ish in 2012 grew up reading issues of EGM yapping about how Sonic "got old"