For a company, matching products and services to demand is what matters. Being able to get more mass into orbit only matters if enough people are willing to pay to get stuff there. The analogy is that jumbo jets exist, but almost no passenger flights bother with jumbo jets because it's not economical. Unlike with civilian aviation we have yet to observe a natural experiment which would allow us to place an economically practical ceiling on rocket payload size, but it very much still remains plausible that something Falcon 9-sized is actually the sweet spot, especially given that Starlink is the only commercial offering that's pushing the existing Falcon 9 capacity.