How much #control do you have on the things you spend most of your time (and make money) - (in technology)?
Social Media, e-commerce marketplaces, e-commerce platforms - we all have just an account, a profile, registration (User Mode). The owner of the platform (and the employees of it) have access to Admin Mode. - Hosting Servers and Cloud Platforms - here you have access to a - ( probably virtual ) machine. You could be the owner of the Application that serves the users, but someone is giving you access to the server and they could have potentially access to the file-system of your machine.
Self-hosted - When you personally run the physical machines and all the software above - you have full control, but also the necessity to maintain (fix malfunctioning hardware, have good Internet Connection, probably should have several servers spread on distance from one another, so if one fails for some reason, the others could grab the requests).
Legal Ownership - When you code as an employee, freelancer - the end result of your work is not legally yours. When you create a service that uses the services or the data of third party - you are becoming dependent - technically and legally to the other and you are subject to being sued if there is no contract about this use.
The tools you use - are they made or owned by you? They could change and break your flow. That's why all big companies have their own - programming languages, editors, platforms, frameworks etc.
Target Platforms - Is the platform that runs your application in mood for change? The browsers change, the Desktop and Mobile OSes change, the cars evolve and are becoming more digital.. Only some basic things like Home Electricity, Engineering and Physics are currently - relatively slow in its evolving.