After interviewing all founders who sold the project, I always asked one question. "What was the actual selling price?" And 100% of founders replied the same number as it was in the asking price.
It's a tricky question. One man's trash is another man's treasure. The concept of relative value is especially acute in this market. Person A may be willing to pay $1,000 for a project, while Company B may be willing to pay $5,000.
In my opinion, prices are pretty accurate on the platform. However, you should count the work done(hours spent), marketing activities, tech expenses(domain, hosting), maintenance, customer support.
Every case is unique, so it's hard to tell about all listings at once.
I can see the micro-aspect as most of these target niche markets, are run by solo-founders, etc., but what differentiates these from traditional small businesses other than the fact they sell digital products and services?
Exactly. The most significant differentiation is that most of the tech projects run worldwide. The founder might not have a permanent place like other small traditional businesses. You could be a nomad with a desktop and Wi-Fi in Bali and travel without being fully dedicated to the business. So, for me, it's freedom.
Sometimes people just don't have enough marketing skills or don't want to promote products but they might have a great potential to make a revenue. In this case, you're right, focus on profit is a great to have to attract buyers.