

From enduser perspective the most visible change would be that all software wouldn’t be hostile to users because with propreitary you have to be very picky to get that.
In the long term we would see that companies could not build walled gardens to block off competition. Contrast Windows & MacOS vs Linux with its different distros, DEs, toolkits etc.
The least difference would be for enterprise because support is expensive either way.
You forgot the first step. The rich man invites him with promise of cookies.