I'd say that "marketing" as used here includes a wide variety of activities, much more than actually buying ads and trying to directly sell your product to peop

I'd say that "marketing" as used here includes a wide variety of activities, much more than actually buying ads and trying to directly sell your product to people. More like - if you have an idea for a commercial website or app or something, it's best to start by finding potential customers, building relationships with them, and getting to know what they actually need and are willing to pay for. This is much more important than what language and framework to use, how you'll host it, and other technical decisions. Do the research first to figure out if people are willing to pay for your idea in a form that's in your "runway" budget of what you can afford to build and run before you get money coming in. It's also perfectly fine to build something without that to try out a new tech you think is interesting, or to scratch a personal itch, etc. Just don't expect to bring in any money with it without doing that research.