Instant communication and fast travel worldwide is a fad
TL;DR: Your great grandparents in North America and Asia couldn't call each other and travel took days to weeks. The situation will be worse for your great grandchildren on Earth and Mars. We live in a narrow window of worldwide communication and travel convenience. The biggest impacts of the return to the slower state of affairs will be in politics and warfare.
For the vast majority of human history, it wasn't possible to send a person or a message to the other side of the globe at all. Whole societies rose and fell without ever even hearing of each other, let alone communicating directly. Eventually improvements in food preservation, horse domestication, and sailing made it possible, but it was rare and took months. Millennia later we got the trip down to weeks with roads and better ships and eventually rails. About 150 years ago we finally had long distance telegraphs, and radio arrived even more recently, finally letting communication outpace travel, with latency down to just hours for relayed messages. In the 1930s we developed international radiotelephone links, allowing connections to be made in minutes followed by communication latency of just seconds. This was shortly followed by international air travel in the 1940s, providing passage around the world in a few days. Finally, in the last few decades, we've seen the rise of jet and supersonic air travel, as well as satellite and internet communications, each providing significant improvements to cost and convenience with minor gains in timing. After those many millennia of accelerating progress, communication and travel time across the breadth of humanity have approximately reached a peak.
Assuming nothing goes horribly wrong, which is not a safe bet with the variety of apocalypses looming ahead, that trend is going to reverse as soon as we have a colony on the moon. There will suddenly be a group of people with a 3 second communication lag, and travel measured in both days and millions of dollars. That's fast enough for an 1800s-style radio conversation, but not realtime control of machines, and the travel lag would make emergency response impossible while the costs will be prohibitive for most purposes. Fast forward another generation and we'll have a colony on Mars or in the asteroid belt, with 6-50 minute round trip communication latency and travel time measured in months. Even approximately realtime communication will be gone at that point, with increasingly many people reduced to sending recorded and written messages to each other, and almost everyone making the trip will be doing so one way. Some time after that, we'll end up with people living in the outer solar system, with hours of communication lag and perhaps years of travel time unless we get a lot better at exotic forms of propulsion. Eventually, if all goes well, we'll send a generation ship or something even stranger out of the solar system, with a destination light years away with matching communication lag, and no way for people or packages to travel there within a lifetime.
Unless we invent faster than light communication or travel, we will never all be closer together than we are right now. Even though it feels like everything is accelerating and a technological singularity might be approaching, these particular trends are likely to be at an end, with major reversals coming in some of our lifetimes.
This isn't just about passenger travel, civilian communication, and business shipping. These changes also affect international politics and warfare. As recently as the mid 1900s it took hours or even days for critical communications to travel from a battlefield to leadership or vice versa, leaving field commanders to make critical decisions on their own. Within living memory, ambassadors were empowered to make deals without the ability to call home in the middle of a negotiation. Only recently has the idea of a head of state making a quick trip to a non-neighboring country become anything other than nonsense. A single commander having direct real-time decision making control over a worldwide military is basically brand new, and doomed to end just as quickly. The mechanisms that governments use to engage with each other and with their populations today will stop working as soon as some of those people and other polities are too far away to reach conveniently. Ask yourself how (or if) the US and China could maintain their international relationships and might if it took their messages a week and their militaries a month or a year to reach each other. Even though these changes are just reversions to the long term norm, I think we've forgotten that and aren't ready for them.
PS: I do look forward to the enforced return to long form communication across asynchronous transport networks. Bring back messages that are minutes long (to read or hear or watch) with minimum possible response times of hours to days. Viva la FidoNet!