Both very slow
How is 150 "very slow"? The fastest trains in Europe, like Madrid-Valladolid run at 350 km/h, or around 215 mph. 215 and 150 is small difference. Then, you should take into account that the distance most European high speed rail connections cover is small compared to the existing Moscow-St. Petersburg, or the under-construction Moscow -Nizhny Novgorod lines are. The distance between Moscow and St. Petersburg is the same as the distance from Paris to Marseille - basically the entire length of France.
We are broke, hence, no fast trains.
A lot of things you say I find reasonable, but this is not. The United States is the wealthiest country in the world by an enormous margin. If it wanted to, it could build a coast to coast high speed rail line tomorrow, for example - by funding it with a fresh issuance of US treasury bonds ($400 billion, $600 billion, doesn't matter). This new issuance would be snapped up within literal minutes, because the US government bond market is the deepest, most liquid securities market in the world. That Republicans and Democrats make a huge deal every year about raising the debt ceiling is just a testament to the economic illiteracy of the rank and file congressman or senator, and their respective constituencies. The simple truth is that it is impossible for the United States to default on it's dollar-denominated debt, unlike a Greece or an Italy whose debt is denominated in a currency over which they have no control. As long as the rest of the world needs dollars to pay each other for goods (a long, long time - sorry crypto folks), the US can infinitely borrow to pay for nice goodies at home. The fact that the US isn't doing this (despite urging from the brightest economic minds in the country), is a function of the average american's puritan attitude to debt - not that the country is broke.
Finally, the reason HSR doesn't exist in the States (despite a seemingly obvious need - there are 50 million people living between DC and Boston), is because Amtrak management are some of the biggest crooks in the United States, and also... because shuttle flights between DC and Philly, NYC, and Boston run every 10 minutes and are cheaper than a train ticket. Sure you'll have to catch a bus or shell out for an Uber once you get out of the airport, rather than disembarking in the middle of downtown, but you'll still make it there hours before you would on a train.