I doubt your profit margin per ticket includes over head costs. Is sounds like it’s mostly direct costs that are included. If your shop truly had a 70% profit margin the owner would be loaded, for every 100k you charge customers they would be taking home 70k in profit.
Not sure if you are being sarcastic and think 8% is huge or you are being sincere and think 8% is poor. 8% is average compared to other industries.
I see you got as far as supply and demand in your economics course before you zoned out. Competition specifically 3 competitors has been shown to apply sufficient pressure to stop price gouging. Airlines profit margins are at 8% which indicates sufficient completion.
I found running in circles around large hoards of enemies and letting my champions do my dirty work was pretty effective. Shooting muddle buds and waiting around is just as boring.