Is Amazon the best example of this? Their retail arm was never long term loss making in the way e.g. Twitter was, if I recall correctly, but rather more like break even because all profits were ploughed into growth. I don't know how much money Amazon raised but back when Bezos started out there weren't the same kinds of insane sums being tossed about by VCs.

Also Amazon's moat isn't really its website, which is mediocre at best, but its backend systems like fulfillment. Plus brand recognition, size, general efficiency etc.