A huge part of the failure here is misunderstanding the budget of the target audience. The author genuinely thought that photographers have hundreds of dollars of cash hanging around to spend on this SaaS tool, even after meeting a customer who explained that they weren't willing to pay for this.

How many hours would this tool save per day? One at most? Even generously valuing the customer's time, the ability to recoup the cost of the subscription at $500/mo is essentially impossible for everyone except a tiny fraction of a percent of potential customers—and I'd suspect those folks don't know they would want or care about the tool.

The author was—at every step—more concerned with making a profit than solving a problem. You'll simply never build a compelling product (and turn a profit) if you don't even know who the people who are supposed to buy the product are.