So why do so many people seem to think Linux needs to become bigger on Desktop?

Personally I am not looking forward to the consequences: capitalism will make sure there will be something on Linux to make money off. They will try to conquer it, introduce walled gardens, stores you will have to pay for, by watching ads.

Android was Open Source once until Google decided to mainstream it.

A pretty important point is that Linux doesn't come installed on many devices. For most people, they buy a computer with Windows or Mac already installed and they're satisfied with their experience. They don't feel the need to find a distro, mount a USB stick, navigate through the BIOS, run an installer that wipes their hard drive, and relearn another operating system when Windows and Mac does everything that they want. When Linux comes pre installed on devices such as the Steam Deck or Chromebooks, Linux usage soars, though these devices have to use Linux because they need a heavily customized OS for their specific purpose. Laptops and desktops intended for casual use that come pre installed with Linux are far less common, so for the overwhelming majority of users, Windows or Mac is what they get and what they end up using. I wouldn't be surprised if Microsoft switches from charging for Windows to paying manufacturers to put Windows on their computers to get users into the Microsoft eco system if Linux became an actual competitor one day

There isn't one simple reason for it. There's a fairly large set of complicated interrelated reasons some of which require going back over 40 years of history to explain. If things had gone differently we'd have had a different result. For instance, just off the top of my head here, if free software had arrived earlier the network effect where everyone wanted one particular operating system because it's what everyone else was using and therefore all the software was written for it might not have happened. People would've been free to build and distribute things for whichever OS they preferred. If Bill Gates hadn't been such a sharp business dealer, maybe his company wouldn't have amassed the vast wealth and influence required to dominate things so thoroughly back in the 1980s. If American antitrust law hadn't been defanged maybe it would've stopped him, because many of Microsoft's business practices that allowed them to get the monopoly we're still recovering from were quite despicable. If DRM (digital restrictions management) hadn't caused problems for Linux such as preventing it playing DVDs for the first few years they were popular, maybe it would've got further by now. If education systems around the world did a better job encouraging more people to be curious about how the things they rely on actually work, maybe the switch to free software would be going faster.

Anyway, it's one thing that is slowly going in the right direction for the most part.

Most of the desktop marketiss work machines, most people just us a phone now.

I don't think "one unified distro", or even an "official distro", is possible without taking critical parts of Linux private and closed-source. As long as the freedom exists people will make their own "versions" of (GNU/)Linux.

If any of you are in a position like, teacher, professor, IT... make sure you explicitly support Linux usage. Try hard not to require software that doesn't run on Linux. I think this would help a lot.

no one unified distro to keep things simple (thread OP)

Debian. Ubuntu. Arch.

In some sense Gentoo, because it keeps configs simple.

Juat to give a good refeeence for tech illiterate people are. Neeva was a searxh engine that shur down a few month ago. They used a subscription model. They had little probelm getting people to pay they had a problem explaining what a search engine was. Their biggest hurdle was, i am not lying about this, getting people to change their settings. Yeah the thing that takes a few click.

Most people care about privacy and what os they use to that same extent as brand of motor oil they use.