Might be one those situations where Excel continues to be applied while the circumstances truly require a database. To at least generate the reports.
Data volume increases, computations get more involved, reports added, there are more and more special requirements, etc. all mandating Excel to jump through the proverbial "hoops".
A once simple spreadsheet becomes a clunge that even the author can no longer manage it.
Excel has come a long ways beyond just number crunching but Excel is not a database.
But all so many people find "database" to be too intimidating, scary, confusing, etc.. And generally unwilling to make any effort to step up and to learn easier and more productive, flexible, and expandable products. Not even to make their own work and life easier. Or less stressful perhaps.
Or just too afraid of change. Or even worse, the powers that be won't permit the risk. Even if parallel systems are run to permit full testing and validation. Sad.
Yet overall one can use Excel tables as the "back end" and Access as the "front end" to do all so many things much easier. Very straightforward to link data or import/export between Excel and Access.
Have made a few converts along the way - but many not. First problem with a database and they regressed....
Some sample spreadsheets, as has been suggested/requested would be helpful.