I think the idea is that buyers prefer that the total price be displayed as soon as possible after pressing Search, rather than right before they make a commitment, which could be several screens later.
For instance, when I go to the Marriott website and look for a room for tonight in SFO, I’m shown the price of $131 once I select the room type. However, when I select it, the next page shows $148.73, which is the room + the tax. Guests are preferring to see $148.73 on the previous page. To me, it’s a minor point (maybe because I’m so used to seeing the tax added at the very end) but the current generation of consumers are getting quite up-in-arms about this as of late.
I think that some industries have been similarly browbeaten about this and have responded. For instance, when I go to rent a car from Hertz, or to book a flight on Southwest Airlines, I see the total, including taxes, immediately in the search results. Rental cars in particular used to be really bad about this, with the total on the last page being sometimes close to triple what was shown on the first page, once taxes and fees were added.
The current generation of consumers has spoken, and companies are starting to listen. There are still many websites that don’t show the total after tax price until the very end. I expect they will hop on board soon enough.