Himanshu,
We have clinical trials -> FDA regulatory process ->Price skimming
and then we can see it near to us ... loooong way to come to gene therapy.
Regarding recruiting more patients: clinical trials are normally the most costly affair in the process.
By the way Himanshu not to confuse with David Levy's BMT with gene therapy, he gone through a unrelated full match BMT, not gene therapy.
Regarding low price BMT, assuming you are from India let me tell you if you have complete HLA related match (not just siblings it is also highly possible to find a related donor in cousins) then it could be done in five lac (RS 5,00,000).
Regarding BMT in older patients it has been there for a while we are excited here as he is one of us we talk.