I'm arguing that the fundamental difference between gambling and insurance is the presence of a large loss that's necessarily linked to the large gain.

By only looking at the net benefit, you're arbitrarily ignoring that. Of course if you ignore the thing that makes them different, they look the same.

Large is a nonspecific value, as is the valuation of the loss. Is the $1000 life insurance policy large? The limit is practically somewhere around the lifetime administrative costs or we would see even smaller (like you do in non US countries). I don't know the smallest insurance limit in rupees, but it's tiny.

If I knick a priceless artifact (e.g. baseball card), the loss is practically nothing, but socio-economically noticeable via devaluation.

"Professional" gamblers treat gambling as trading time (looking for opportunity, like in Poker) versus risk. Bad gamblers (e.g. slot, roulette, etc) play out games where there is no possible benefit from time investment. No consistent reward for trading any commodity.

There's no difference between many kinds of gambling and insurance, other than the regulations and mediums involved. The insurance companies are still managing risk vs reward.

The difference is whether or not this scenario can happen: you put in some money, get out much more than you put in, and end up far better off than you were before.

With insurance, only the first two parts can happen. The third part can't happen, because the second part only happens to compensate you for a loss. When gambling, all three can happen. Of course, on average it won't, but it's possible to put in a dollar and get out a million dollars with no losses besides the dollar and a little bit of time.

It is sometimes possible to arrange all three with constructs we call "insurance," like taking out a life insurance policy on someone you don't like, but my argument is that this is where we start to see insurance as "wrong" too.

I'm playing the heel here. Your point is well-taken, in that insurance prevents large absolute loss rather than the potential for large absolute gain.