Meanwhile the SaaS business model continues to eat the software market. A model that gives users less control than the desktop software model. And where the source code (built on open source) is not visible.
Open source software has been critical to the success of the SaaS model. You could argue SaaS is the true success of the 'open source business model'. Just not in the way open source advocates expected it to be.
There is another option - one that some open source advocates will immediately dislike: source-only products i.e. you sell your software product to customers to run them themselves. You give them the source code of your product so they can customise it to meet their needs. But the software is not open source and cannot be shared the way open source can.
There are successful source-only products. Two examples: Craft CMS and Kirby CMS. Both publish their source code on GitHub [1] [2] and rely on the honesty of their customers to pay (which they do). They have a thriving community of developers making plugins and extensions - proving that you can create a community of developers around a 'source-only' product.
[1] Craft CMS: https://github.com/craftcms
[2] Kirby: https://github.com/getkirby