If you enjoy cooking, then time spent doing it isn't a pure cost. Many people enjoy cooking. I happen to be one. You might turn out to be one too.

Sure, but the OP, at least, doesn't sound like one of these people, and I doubt he's alone.

Cooking is a useful social skill as well as a way of getting edible food for yourself. (You can invite people over for meals, which is by no means socially equivalent to inviting them out for meals.)

Even if I learned how to cook, it's unlikely that I would end up being the best cook in my social circle. If I want eating-at-people's-houses events to happen in general, I can subsidize the best cook in my social circle instead of cooking myself. If I personally want to be the cook to win friendship points with my friends, that might be a good strategy, but it's probably worth thinking about whether I have other strategies that play better to my comparative advantages for winning friendship points.

Beware of simple-minded time/money tradeoff analysis where you assume the value of your time equals (or even is well approximated by) the amount you are paid. That's a safe assumption if you actually have the option of adjusting your working hours ad lib and your behaviour is perfectly consistent, but not otherwise.

Agreed. I'm basing my current conversion rate on approximately the hourly rate I can get tutoring, and I have substantial leeway to adjust how many hours I spend tutoring. (LWers looking for extra cash who have good academic credentials and haven't considered this possibility should do so; with good credentials and in a reasonably well-off area you can safely charge $60 an hour if not more, and you can use a service like WyzAnt to minimize the time cost of advertising your services.)

Cooking for yourself may well get you a healthier diet; you need to consider how you value your health as well as how you value your time.

Sure. This is why I no longer eat at restaurants for all of my meals; again, for health reasons, half of them consist of fruit, hard-boiled eggs, and whey protein (none of which require cooking, really; hard-boiled eggs are very easy to prepare).