Building for fun vs building for profit are very different and it's important to set your intention for a project, even though the line often gets blurred.
When you are building for fun, it is for yourself. When you are building for profit, it is for other people. When you are building for fun, you get to decide what to work on and when to stop - usually when it is no longer fun. When you are building for profit, other people decide what you work on and when you are done - usually when no new features are requested, you have no competition, and you have absolutely saturated your market. This rarely ever happens so you always have something propelling you.
The biggest failure most engineers encounter is they build things nobody asked for. They build products without customers lined up, for markets that do not currently exist, with only feedback from themselves. This is because they built the product for fun thinking they were building it for profit.
The line between the two is very easy to blur - especially when reading OP's blog where he genuinely sounds like he had fun building his projects, but I guarantee there was also a lot of very unfun background work done in the name of profit.
When you are building for fun, it is for yourself. When you are building for profit, it is for other people. When you are building for fun, you get to decide what to work on and when to stop - usually when it is no longer fun. When you are building for profit, other people decide what you work on and when you are done - usually when no new features are requested, you have no competition, and you have absolutely saturated your market. This rarely ever happens so you always have something propelling you.
The biggest failure most engineers encounter is they build things nobody asked for. They build products without customers lined up, for markets that do not currently exist, with only feedback from themselves. This is because they built the product for fun thinking they were building it for profit.
The line between the two is very easy to blur - especially when reading OP's blog where he genuinely sounds like he had fun building his projects, but I guarantee there was also a lot of very unfun background work done in the name of profit.
Edit: Don't just take my guarantee for it, read about his challenges for One Item Store https://tinyprojects.dev/projects/one_item_store