I also wonder how much more speed can we get? 5000 Miles per hour possible? Making Anywhere around the world possibly within 2 hours flight.
Also wonder on the bottleneck being inland transport and Check in.
I'm not sure I would like that hypothetical world, because that beach would be crowded beyond what one can imagine, or, alternatively, controls would be implemented to manage crowding. For example, if people now are willing to spend $500 to travel to Rio, and the price drops to $5, one could easily require non-locals to buy beach permits for $100 a day or $250 a week. The best beaches could even go higher and aim for the jet set as, for example, Monaco already does to some extent, and China and Nepal do for Mount Everest.
So far, things seem sort-of OK, but of course, people would flock to other places as well. Millions would want to visit the poles for a few hours, see total solar eclipses at the most remote places, and the trek of the wildebeest would be dwarfed by the trek of the tourists. We would need lots of new rules to protect natural habitats that now partly are protected because that are so remote.
Not sure how things shake out as these transportation trends evolve: do you still have a tendency to crowded areas, or do you actually end up getting more diffusion. Suburbs were the city planner's utopia for a long time, but traffic and feelings of lack of community ended up making them less appealing than originally imagined. Maybe the suburb approach becomes more compelling again if problems of traffic & lack of community are addressed.
Even if we ignore the ridiculous cost of $5 for the travel itself, what about the cost of travelling to and from airports? Uber, trams, trains, car and hyperloop all will cost money.
Are we going to have an airport in every suburb? I thought not, so that adds quite some travel time. If not using your own car then you have to wait for the Uber, tram, train, hyperloop to arrive as well.
I guess the plane will carry no baggage so that travellers can get straight on and off without any delays. Just hand luggage everyone!
Let's consider what some of the things that would need to happen are to address the problems you bring up:
Cheap, virtually free sources of energy would need to play a part. To solve the issues of airports, maybe it's that we have personal flying crafts capable of vertical takeoff instead of relying on centralized airports. Maybe there's a way to get picked up by an airplane at your house (not saying I have any idea what that might look like, but it gets you to start imagining approaches around the constraints). What would possible solutions to the baggage issue you brought up be?
This thought exercise prompts is meant to prompt ideas around what things could look like in the extreme, so that we can then consider what might need to happen to get to something like that. For sure there's lots of hurdles, and some of them may actually be fundamental limits - though I'm not sure that such limits exist here.
Last point I'll make is that economic assumptions do change over time substantially. Until the industrial revolution in the 18th century, economics looked very different than it does today - GDP per capita did not increase as any increase in GDP was met by a proportional increase in population (https://en.wikipedia.org/wiki/Malthusian_trap). The assumptions we have about how our economy functions today could dramatically shift over time as technological advances shift the dynamics of the system. Abundant food, energy & energy storage, along with automated skilled robotic labor, could challenge many of our current economic ideas.