Author here I actually think spreadsheets are great because they are so accessible. What isn’t great though is when there is a business processs that is a spreadsheet and knowledge that exists in one persons head.
It is a management failure when this is in only one person head.
Outsourcing tools will not solve internal management problems.
The issue with excel is that there's no standard construction that anyone can query; most likely it's extremely hacked together since it's not a database, but made to look like one. Spreadsheets are great for doing stuff related to exports or before importing, but so, so often they lead to data islands built to either actively or passively protect someone's job.