>>We could have designed for this audience, but at the expense of more numerous, savvy users.
Of course, that could be interpreted as snide. Very snide. Pardon me, I feel I must respond from a perhaps cynical perspective, but in the spirit of HN, this should not be interpreted as a personal attack, please consider it as a form of customer feedback resulting from real-world experience...:
Lets imagine your unsophisticated user wants to buy something. Your team has made sure the desired product is splashed on all the relevant search results with vim and vigor, nay, it hunts them down with delightfully appealing charm. Then the not-so-savvy target follows the trail, most assuredly identifying themselves as an eager customer, providing all sorts of delightful self-identifying information so that future marketing will surely be able to follow up with grander offerings specifically targeted to their needs! Sadly, the little "in-stock only[ ]" checkbox was ancillary to the much more important (as determined by high-quality tests run by the best consulting firms or maybe just lower-cost magical thinking) page features like "buy this immediately" button and "most popular choice" banner. Thus the user guided by top-notch design immediately launched into the purchase process and enters payment and shipping information as prompted, then clicks the final checkout button only to be informed by pop-up the item is out of stock! To add insult to injury your site actually authorizes the payment and says the item is backordered and thus delivery may be delayed N+1 weeks, where N is the limit of what any reasonable person would expect and WTF didn't it tell them before it went down this rathole.
At which point my spouse/parent/adult child comes to me and asks me why they found this thing to buy but they can't seem to get it...to which I reply, this is a scam, cancel payment if you made it and don't fall for it again. You gave them your email address, so they'll be sending you scammy emails trying to get you buy more non-existent stuff that looks perfectly wonderful to you because they know something about you, like a con artist would pitch you. Make sure you block them. If anyone tells you otherwise, it's a high probability they're either misinformed or getting paid to hook you into another round of pointless web-surfing for nothing...except maybe glittering eye-candy.
Of course, capitalism is wonderfully insensitive to your morals and remarkably efficient (capitalism is just an observation, not a theology) and even if you build your business on a tower of socially tolerable deceptive and user-disdaining practice, well "there's a sucker born every minute" so you may likely still develop enough margin to succeed in your enterprise, and may thus afford to disdain those less savvy users...