Doe the fiber optical cables that carries internet make as much profit as internet - of course not. But without the fiber optical cable - there would be no facebook or google or these trillion dollar industries. If private sector is allowed to lay it - it will never lay it in unprofitable areas.
Gov is NON-Profit. If we wanted to maximize profit - we would go back to Darwinian existence - survival for the fittest/strongest/most profitable.
Gov provide security, military deterrence, infrastructure and all these non-profit making things that allow individuals and private sector to profit from it - and then pay taxes.
Or let say gov profit is not in monetary terms - it count profit in having cohesive, secure and safe communities.
If gov built a bullet train - it doesnt have to turn profit for 100 yrs - but the time savings, the fuel savings, the less accidents, the comfort for its citizen - that is the real profit.
US has spent 1 trillion dollars in Afgan - fighting - if it look at it form profit-loss - it would never have engaged.
Anyway bottomline - US infrastructure is so 1950s - countries like China are building next generation infrastructure - making life for Chinese better than the US.
While you have to live 150kms and commute with you car - a chinese get into a bullet train - and is at office 20mins later - living in the same distance. In fact another decade - the only thing you have better than chinese - is the freedom to insult politicians
Governments esp Western ones build undersea fiber optic cables more for eavesdropping not altruism, private companies used to lay telegraphic lines across the Atlantic so it can be done without government. Fiber optic cables are profitable on their own without government subsidies unlike stupid trains you are so fond of.
I need to educate your primitive mind, first of all governments don't make money, they confiscate it from us by force. Government should only do THREE things:
Military, Police, and the courts to protect citizens from aggression, theft, breach of contract, fraud, and to enforce property laws. Hayo tu, otherwise it is an invitation to characters like Ruto and Uhuru to decide the winners and losers in the market place and you end up with endless grand corruption, impoverishment and no progress. Get
serikali out of business altogether and you end up with clean government. Simple.
America DOESN'T NOT NEED BULLET TRAINS,

planes are much more cost effective. Why you waste days on rail when you can go coast to coast in hours

Common sense
US infrastructure is actually superb for the most part don't listen to naysayers, parrots, big government big deficit loving liberals and cronies. What America needs is to come up with ways to make users pay for the infrastracture they use, right now they tax gasoline but with electric cars coming up it doesn't make sense. A mileage based user fees would be the best idea.