True, but it also takes more time for the bot programmers to modify their bot in order to get it to work for the custom layout of the page with captchas and limits, giving actual people at least 5-10 minutes from when the sale goes live before the bot is working correctly to purchase everything. Unlike what happened here where people were sitting there refreshing the page and between when they could click on the purchase and actually fill in credit/shipping info all cards were sold out.
There are also other alternatives instead of captchas that can be implemented on a page, such as tracking the time it takes to put in the information for the sale. It is pretty easy to run some time tracking for test selling internally before you make the page go live to figure out how long it takes on average to type in all the information by hand as a person would do and the check to see if that informationwas input faster than a human could do so and block the sale... That at least would force the bots to operate on a similar playing field as the regular people who were there waiting for the sale to go live.