It's not required that people rely on data centers and cloud computing, those are just choices that people make. It's a matter of convenience and economics - it's now cheaper and easier to host a site at a server farm, than to manage your own server. You can still choose to set up a server in your basement, and maybe have a failover cloud strategy in place if traffic gets busy. It's just more work and moeny.

You don't have to rely on programming paradigms involving a great many dependencies and lots of computing overhead, which are hidden by fast CPUs and GPUs. You can write code carefully in low-level compiled languages, knowing bugs will be a problem, but creating small compact binaries. It's just more time and effort.

There's a real trend towards what one might call retro-computing - having a RPi server on your LAN that you back everything up to, maybe some long-term encrypted cloud storage (or just an encrypted USB drive in a safety deposit box) for disaster recovery, but not for regular usage - and only using applications with local client-side data storage, and so on. Never pay for Saas, never lease proprietary software, pass laws that make it illegal for your personal data to be stored in some corporate database for marketing and advertising purposes, etc.

You don't have to buy what the corporate computing world is trying to sell you, in other words.