The American way of doing things is to advertise the price before all of the fees and taxes. This is totally opaque (by design, I might add)
The easiest way to get a real cost is to submit and sign up, wait for the first bill, and then and only then you get to see the true cost. Trying to piece it together is bordering on an exercise in futility. I could almost argue that you are wasting your own time (depending upon how you value it by trying to get to the bottom of all the taxes and fees) You just need to make sure the contract is month-to-month so you can cancel it if you think the taxes and fees are unreasonable.
Maybe a progressive state such as California could require complete disclosure of the total monthly cost at sign-up, since they should have all of the information at the end of the sign-up process to determine this.
I think all of this boils down to American Culture, and the fact that Americans don't seem to care as much on the bottom line costs compared to the rest of the world.
American consumers just don't signal that transparent pricing is high on their priority list.
Americans pay sales taxes and don't have the final price at their fingertips without using a calculator. This is presumably so one can figure out how much tax they are paying for an item, but I think the real reason is to make the cost not seem so high when they're deciding whether to purchase the item or not.
The Europeans pay value added tax on goods sols, and the price tag shows the price they will pay when they pay for it. This is the preferred system. 100% price transparency.