They probably could, but it would be worse. I worked for a few years with the opposite, replacing spreadsheets with systems with custom interfaces, backed with databases, access control, real backups etc. The savings (in form of reduced need of manpower), quality and reliability increases have often been enormous for these customers.

Sure, but the question is one of stability and consistency.

Take data input: You want your front line workers to record every time they do thing X. They could go into a spreadsheet and increment the count by 1 (or add a new entry in the row each time) or they could pull out their phone and open an app and press +1X, with the option of -1X if they make a mistake.

Which one is going to be better quality data?

I would say 75% are replacing a spreadsheet.