Salesforce and Apple are different
Jobs kept things under his hat until the last minute and then showily announced them because Apple have an established base of extremely (or insert less flattering noun here) loyal fans who await each new announcement with wallet at the ready.
Announcing new stuff in advance would kill the magic.
Salesforce, on the other hand, have an absurdly inflated share price based on 'thought leadership' and so Benioff needs the analysts to suspend disbelief long enough that he can offload as many shares as possible without panicking the market. A long, deep roadmap of apparently game changing products is key. Delivery of said products doesn't matter until phase 2 (reality sets in. Share price crashes, 'visionary' ceo leaves and board pick up the pieces to see what kind of a business is really there).
When your business is built on bluster you have to keep heaping it on, because when the music stops you have a real Facebook situation (share price crashes, people wake up and wonder what was going on).