The 20th Century brought tremendous change: social, political, and technological. I was born almost smack dab in the middle of the 20th century; I didn't own a cell phone until I was in my late 30s.
The cell phone was one of the biggest changes of the 20th century. It started as purely a communication device, a way to reach people from anywhere. After 9-11, I bought for one for my daughter, who was only 12, because I felt a tremendous need to be able to contact her any time. Her older brother already had one. Now, they are ubiquitous. When I read old books, I can figure out when they are set by whether or not (and how) the characters use cell phones.
Over the years of their existence, cell phones have added all kinds of functions. The smartphone I take with me everywhere -- on those rare occasions when I forgot to take it with me, I felt naked and vulnerable-- is now my alarm clock, timer, camera, web browser, email device, social media interface, and road map, as well as being my phone.
Change is still proceeding, at a rapid pace. TVs are now "smart," cars can, to some extent, drive themselves, TV remotes can accept voice commands, and household appliances can connect to the internet. Some of the changes are very small but also very useful. I love being able to set my dishwasher for a delayed start time of midnight because if it's not totally full, I can add in any dishes I use that evening and not worry about forgetting to start it. Likewise, the remote control for my cable service set-top box lets me set reminders and then auto-changes the channel to the program I marked when that program starts. This is especially useful when I want to be sure to watch part 2 of something, and also when a show ends or starts at an odd time; I watch both The Daily Show (Trevor Noah) and The Late Show (Stephen Colbert) almost every weeknight. The Daily show starts at 11:00 pm and ends at 11:45. The Late Show starts at 11:35 and ends at 12:35. Without an auto reminder, I would most likely miss the start of The Late Show, and their cld opens are often epic.
The growth of the internet has meant that many things that used to happen in person or by snail mail now happen online. Online shopping and social media are two examples. It's difficult to keep up with the various social media sites. I'm good with Facebook and Twitter, but I have limited skills in Instagram and none at all in Tik-Tok.
It's safe to assume that assume that science and technology will fix many things that are problems now. The incredible speed at which vaccines have been developed for COVID-19 demonstrates what can happen when a huge number of people and resources are dedicated to a single problem.
One of the most fun things about writing fiction set in the future is deciding what problems will have been fixed-- or sometimes what problems will have been created-- by technology. I would like to think all housework would be done by robots (I call them servoids in my books) and I would certainly hope we would find cures for diseases that kill or limit so many people, like cancer and the many varieties of autoimmune diseases.
Note that one of the earliest attempts to see the future via science fiction was H.G. Wells' The Time Machine, which actually pre-dated the Twentieth Century by a few years, Of course, Wells was way premature. We still don't have time machines. Yet.