I am not a conspiracy theorist, but there is no doubt that BIIB could have done a better job of selling Ty.
Mullen has admitted that he has refrained from pushing it because of PML potential - plus Avonex is/has been their MS franchise drug. He is - as a CEO needs to be - bottom line-centric - he does not do "Patients first".
To me - that's a conflict. Ty is a more efficacious drug and with the TOUCH program, the chances of contracting PML become ever smaller as the possible causative factors become understood.
Back in ancient days, the Druids thought black cats were human beings.