A v2 Starlink satellite costs $800K and on average 25 are launched at once. Launch cost for a reusable Falcon 9 is $15 million. So that's $1.4 million per satellite to orbit lasting 5 years that's $280K / sat / y, or $2.8 billion / y to maintain a constellation of 10,000. And SpaceX is not known for complacency. The unit cost will continue to drop.
On the other hand there are currently $63 billion (22.5 years of Starlink cost) of rural broadband subsidies active in the US and it hasn't come close to running all that fiber. So $63 billion to not even finish the US vs $2.8b / y to provide service to the entire world. I think it's safe to conclude that the satellite option is in fact much cheaper.