Starlink is not a substitute for fixed broadband. It might be adequate for most use cases, but it's not equivalent and it never will be. Your "99%" figure is nonsense. More than 1% of people will see the difference in download speeds between 1Gbps and 300Mbps. You realize some apps and games show you information about latency and bandwidth?
Also, just because they advertise "up to 305Mbps" doesn't mean everyone is getting that. A friend of mine with Starlink in the midwest gets about 100Mbps during off-hours. See <https://www.ookla.com/articles/starlink-us-performance-2025> - median speeds are typically less than 150Mbps.
Starlink also costs about 2x-4x as much per Mbps as 1Gbps service (at least where I am). I doubt they're going to suddenly offer 1Gbps speeds in the next year without changing their pricing. They'll add a new, more expensive plan.
Even 1Gbps Starlink (which would be more than 3x the current max speeds) is going to have other differences such as increased latency (they mention 30-40ms in one place, 25-100ms in another), more jitter, and lost signal sometimes during bad weather. Starlink also uses CGNAT which eliminates a bunch of use cases and introduces its own problems with certain apps and games.
They've had issues with capacity before where they wouldn't accept signups for some areas. Adding capacity involves launching more satellites.
Starlink isn't the ultimate solution to everyone's Internet access problems.