One thing overlooked by the article is that portfolio management and other similar applications often involve "trade secret" proprietary analysis and evaluation

One thing overlooked by the article is that portfolio management and other similar applications often involve "trade secret" proprietary analysis and evaluation methods. It's way easier to build, manage, and protect that sort of IP in a spreadsheet than in other application environments. In particular, it's reasonable to be leery of software that requires paying the vendor to customize it, since at least some of your methodology is almost certain to leak to competitors. Excel has many faults, but it does allow you to keep everything behind your own walls, with no dependencies on vendors, consultants, the cloud, etc.