This quote is completely and totally irrelevant. Nobody is saying they should code a new Outlook. If they did code something, it would be significantly smaller in scope and rigorously tested like spacebound programs in the past were. "New space-engineering-grade code created with actual engineering practices" is absolutely going to be more reliable than "old bloated commercial shitware". But I guess software engineering is a lost art, so it can't be helped.
It's also going to take a hell of a lot longer and cost more than buying an Outlook license. If I was lead on that project, you'd have an uphill battle trying to convince me that spending $100k+ on an email solution unless you can point to specific, serious deficiencies in the existing off the shelf solutions.
Software Engineering is far from a lost art: part of the practice is intelligently making cost-benefit decisions.