If the answer is no, then the smart developer has no financial incentive to do so, and every reason to segment security out as a premium feature.
Maybe MITM vulnerability counts as broken code. But as always, markets win. I don't think the status quo will change until users consider security assurances worth hard dollars.
This reinforces my priors that there is very little "free-as-in-beer" software.
Think through that a little more and I think you'll find there is long-term ROI in the form of customer trust and goodwill. You'll buy the product because it works and won't hurt you, and basic security should be part of "won't hurt you".
Right! And that's actually a valid model. Ask HP about what it'll cost to upgrade the firmware on your enterprise server..
[1] I had a boss who insisted that TJ Maxx was going to collapse because of their security holes. Nope.
It should be no different from shipping broken code. You can't just say, "oh, well we offer a premium build that actually works, for users that want that." Everybody needs it.
Evernote made this mistake initially when SSL was originally a premium feature. They fixed it.
Granted, there are degrees of security but protection from MITM attacks is fundamental. (Especially for executable code!)
[1] https://twitter.com/mveytsman/status/491298846673473536
UPDATE: @weekstweets just deleted the tweet I was referencing where he described security as a premium feature "for users who desire it" or words to that effect.