How would the mainstream view it?
How would software support improve?
How would gaming look like?
Which country will become the first Linux majority? India? Seychelles?
How many local governments would start adopting it?
What year do you think it will happen in?
It would likely look like versions of the three most popular forms of Linux today, Android, ChromeOS, and Steam Deck.
Very likely, it would be developed to host a vendor’s app store as a way to make money. Depending on the company, it would likely give admin access to users based on corporate preferences similar to how Android phone sellers lock or unlock parts of the phone. You can still install your own Linux to some computers, but that market would likely remain the same size it is today.
I also see some companies with a business model like Stripe deploy specialized Linux computers to businesses designed to deployable to large companies and have a longer lifecycle than a Windows OS. With payment of these computers likely done on a material + maintenance program, updates to these computers would likely focus on security and uptime only. Some individual large companies may even have their own flavor of Linux, like a hotel chain deploying terminals across corporate and franchise hotels and tied to corporate servers.