Not asking you to dox yourself, but that number outside of context means very little.

If it costs almost nothing for a competent city and your city is spending $150M/year on it, well then the obvious conclusion is that your city isn't competent! 🤓

But seriously, though, it's funny 'cause it's true: almost every city in the English-speaking world is incompetent at building bike infrastructure. The correct way to do it would be routinely as part of the standard operating procedure of maintaining the street. When you break it out as a separate retrofit project and then hold a big public input process about it, of course it's going to massively inflate the cost.

(Also, I'm pretty sure @regul was talking about the costs only for upgrading bike lanes from unprotected to protected, not the total cost of bike infrastructure in general.)