Luckily, I have never actually made a cumulative profit renting out a single sim since 2008, and mainland in 2007 (Its gotten easier to make a profit now that sim fees are down to $229 a month from $295 a month)
Since Nov 2007, my estimated cumulative net loss has been -$2973. Since July 2018, when tier fees were reduced to $249/mo, then $229 in June 2019 , my estimated net profit has been $493