Looks like you've been right, so far. I agree, built in 100% inflation is not a good recipe for a currency. The fact that 90% goes back to SP holders does not really help, because SP is not liquid. When you hold liquid steem, as I understand, you really do suffer 100% annual inflation. Growth in demand could compensate, but 100% annual, sustained growth is unrealistic.
Steem dollars are another interesting issue. Experience tells that every attempt to fix currency exchange rates eventually fails if there is an open market for both sides.