I wonder if you could have found success asking those companies if there was anything that the tool could do in addition to helping find files that would make it worth paying for, did you by chance try asking this? Sometimes startups pivot to nearby goals, and it works out. I have a feeling out there is a company you could have appealed to, maybe not 100% with just "find files fast" but maybe "find all x files, from x date, and x client"