Just because something is “good”, which is always subjective anyway, does not mean it should be embraced. Market share aside, Linux is not that friendly to normal people even today, though it highly depends on the distro and not Linux as a whole. A simple thing: if Linux is so good, why there are very few people using it as desktop system?
Ok, I will stop here for now.
A couple of points here on the status of Linux. Yes,
some distro's of Linux are not friendly to normal people. Distro's based on Arch and Gentoo clearly fit that bill. However, other branches of Linux like Debian can be very user friendly, like Ubuntu, Mint and Pop!_OS. Also Red Hat based distro's like Fedora can also be quite easy to use. All of these are typically no more difficult to install and use out-of-the-box like macOS and Windows.
Linux is very good, but it's not widely used in the at-home desktop environment because the early days of the OS were very much difficult and CLI-based. The early days being the mid-1990s. Compare that to macOS and Windows which got their start in the 1970s to 1980's and marketed themselves to the at-home and business users. Additionally, the OEM vendor's like Dell, Gateway, Lenovo et al. have license deals with Microsoft to sell their boxes with Windows on them. You can get Ubunutu on a Dell computer by ordering them that way, but it's a niche market for them and not really advertised. Same thing with Apple, they sell their boxes with macOS on them (obviously since they make both pieces).
Also, Apple and Microsoft are proprietary monolith's with centralized distributions for their OS, and their OS only. Linux and *BSD are all community driven and decentralized. IBM's recent acquisition of Red Hat and Canonical's ownership of Ubuntu are a discussion for a different day. But, with Apple and Microsoft, who knows what can happen next month or in 100 years from now with these companies. They could be gone at some point and their intellectual property (i.e. macOS, Windows) could disappear. With Linux, the software is open source and freely available to anyone and decentralized - the chances of it disappearing are slim to none.
Linux isn't out there to be marketed and isn't out there to gain market share from Apple and Microsoft, nor is it on the stock market to please and make money for shareholders.
Linux is a lot about philosophy and that's where the 'free and open source software' or FOSS come from. Many people mistake the 'free' to mean 'no cost' but that's not it. It's the philosophy of 'free = freedom', freedom from being proprietary. It's about anyone with the desire and knowledge to take something someone else has created and build on it or re-create it their own way and then redistribute it themselves freely.
That's why Linux isn't up there in market share for the daily, average at-home or small business user like Microsoft and Apple are. It's just that its not the stated goal of Linux.