The data broker market is ~$250B, it's not all personal data, but the market for personal data to target these scams is huge. The worst part is many data brokers get their data from government sources like the state DMVs: https://www.privateinternetaccess.com/blog/dmvs-are-making-a...
They probably bought it from some data broker.
They sell our data to scammers to let them be entirely convincing, and then blame people who fall for it.