Hm, well, let's look at those "naked" calculations. I guess you can make ~ 5 ped per flight, so that's like 5 ped per ~ 30 minutes... to recover the cost of your purchase you'd need to work for about 5000 hours. Let's say you have nothing else to do and work 8 hours per day, 5 days a week (16 naked passengers per day, which is an unrealistically high number, having done taxi flights myself for quite a long time before everyone had their own quad). That makes it at minimum in an ideal fairy world, 2 years and 5 months to pay off, working 8 hours a day, 5 days a week. Practically, since you can't get that many passengers--especially since you're competing with 25 other equus taxi pilots for the same few travelers light enough to use the equus warp--you're going to be working more like 10 years minimum, full time, to pay this investment off. Now you may call that "guaranteed profit" if you wish. So is wandering streets looking for lost change. I call it overpriced investment.
Oh and btw a player can lose a lot of money with the equus... being looted of invisible or visible stacks, scamming, or not charging enough to cover costs, price crashing after MA "fixed" price listings end, etc.