Grinding out returns from a sunk cost of a century-old investment is pretty impressive all by itself.
Very few people want to invest more: the private sector doesn't want to because they'll never see the return, the governments don't want to because the returns are spread over their great-great-grandchildren's lives and that doesn't get them re-elected in the next n<=5 (because this isn't just a USA problem) years.
Even the German government dragged its feet over rail investment, but they're finally embarrassed enough by the network problems to invest in all the things.