Re: Huge progress?
"The $40m, or whatever it costs a Falcon second stage, will not need to be paid any more."
There have been some estimates that the internal cost for a starlink launch is around $20M. And that includes a new second stage.
When you are launching as often as SpaceX the second stage production line becomes "mass production" driving down costs per unit. They are probably building 8-10 new boosters a year between Falcon 9 and Falcon Heavy - that's more than most non reusable rockets. Driving down costs. Launch and test facilities have high usage which require more maintenance but spread over so many launches drives down costs per launch.
And since SpaceX hasn't reduced the price of launches for customers they are raking in massive profits. They don't need to because they are still the cheapest launch provider, have an amazing reliability record getting the payload to space (which drives down the cost of launch insurance, too) and have the excess capacity to add launches.
It's going to take more than a reusable rocket to compete with SpaceX - it will take having a large launch cadence to drive down all of the costs. Maybe Blue Origin with Kuiper or a Chinese launch provider with China's internet satellite constellation.