Corgan pretty much IS Smashing Pumpkins though, he's always had the power to hire and fire whoever he wants, he rerecords other members parts whenever he feels like it, and he's used that power on multiple occasions. It's widely known that almost all the guitars on Siamese Dream are Billy, because he ditched all of Iha's parts and did them himself, and most importantly, he has sole songwriting credits on just about every song they have released. Iha gets a credit on one or 2 tracks per album the rest is ALL Billy Corgan.
SP is his baby, he's been the driving creative force behind their success, to a greater degree than any single member of STP has. It's absurd and arrogant to suggest he has no right to record under the Smashing Pumpkins brand.
