How are you defining "everything" and "upfront"? Upfront as in the first page shown after searching?
Because many, many airlines/car rental sites have a complex muti-step process of different fares, extras etc until you get to the final stage
Sure you will have upsells but if a price for a service is presented, that should be a final price. You can't tack on "resort fees", the price presented must be inclusive of all the required charges. For example as much as I dislike Booking.com, the price they show for a room includes everything — tax, mandatory cleaning fee and city tax if applicable.
You can go to the last page and book rental. Only at the airport counter you will learn, there are extra fees you need to pay.
I think this supports precisely my point — in EU all the fees are presented such that you can get the service without any hidden costs