I think it's rather good that Peter addresses all the points described here. Indeed 1.5 pounds knock-off is not going to drop the whole under 20 pounds but I'd rather have the founder and CEO of helix give a reasonable, albeit disappointing to some, estimate. I know all too many people in the industry (CEOs included) who'd have waved around the prospect of major optimisation and room for progress. It seems to me like Peter says "enough". He redesigned the bike fully. He took painstakingly long to bring his vision to a compromised by realistic outcome, and I for one appreciate the attitude he's displaying. Development creep and shifting goalposts is a scourge.
good luck producing/getting the bikes!