Starlink Leo satellites are not the same as geosynchronous satellites. geosync satellites are very high up and will more or less stay there indefinitely. Starlink sats will decay from their orbit and burn up in the atmosphere after about 5 years. which means if you aren't constantly launching new sats all the time, the network will quickly degrade and completely fail within five years. in other words, there is way more than a zero percent chance that starlink is not a financially viable product long term.