Now basically every PaaS has a free or cheap (<$50/mo) tier, tons of helpful tools with free or cheap tiers, you can get users / customers for free on social media and probably more effectively than traditional ads / PR coverage.
It’s not strictly true because some projects use GPUs for ML , sometimes there’s some technical rot if you don’t upgrade your stack a bit, market change could make you irrelevant etc
But in general there’s a lot of products that can simmer and slowly iterate for a long time as long as founder keeps chipping away as evidenced here.