This claim of massive savings is ludicrous for an f50 in the first place. It’s doubtful their cost is primarily maintaining and admining fleets of x64 servers, which is what the “cloud” is optimized for. These companies generally have massive costs from legacy mainframe, iseries, mvs etc systems. The ops creds are suspect to say the least.
Your comment would be more palatable if you gave the OP benefit of the doubt. It seems reasonable to assume that someone who is in the position to affect such change, and is willing to ask HN for advice, likely has actual cost savings estimates.
Perhaps saying something like, "Are you sure the cost savings are really there, and you won't face unexpected hidden costs in the future? I have experience with X,Y,Z, and we found that while the cloud is optimized for x64 deployment, we had hidden costs A, B, C, crop up after 9 months."
As it is, it's only added noise and made you look bad.
Your comment would be more palatable if you gave the parent poster the benefit of the doubt.
Perhaps using http://www.paulgraham.com/disagree.html and avoid dismissing the content because you don't like the way they said it (DH2, responding to tone).
He mentioned 90% of their datacenter operations. I assume the remaining 10% would be the assorted legacy every large company has of SPARC, PA-RISC, POWER, i and zSeries accretes over time.
Those will remain where they are and, eventually be ported or replaced (or kept alive - IBM mainframes have been legacy-friendly for over 50 years now) by newer systems as they are phased out.