The Boring Company is absolutely a success and imo it's the best example of Elon's tried and true strategy: convince government officials of some idea only the government could buy. Boring Company is a money making machine just like SolarCity, Tesla, and SpaceX even though not a single one of those companies could be profitable without the heavy subsidization they receive.
Good Jobs First track how much subsidies are given out to specific companies. Tesla's racked up $2.5 billion from states and the federal government and another half billion in loans/bailouts[^0] (for comparison, Tesla' net income in 2022 was $11.19B). SpaceX is all government contracts where NASA basically pays a private company to do the things they could and want to do but can't because of political impediments. We're still the ones funding it, we're just paying more and letting a private company take credit. Starlink's subsidized by the FCC, SolarCity's subsidized by a number of states as well as the federal gov'ts subsidization through tax credits for 30% of the cost of solar panels, etc.
And people aren't dumb. He's been sued in a number of countries for subsidy fraud already. Remember when Tesla pretended to have rapid battery exchange ready to go and announced it was live? That was purely to take advantage of a poorly written subsidy package in CA that didn't actually stipulate they had to give people access to it. Tesla won that lawsuit too iirc.
Elon Musk became the richest man on earth without ever running a profitable company. In fact, I'd say it's precisely by NOT running profitable companies that he got to where he is today
[^0]: https://subsidytracker.goodjobsfirst.org/parent/tesla-inc
edit: grammar & typos