Quote:
I'm basically looking for reassurance that whatever database system we are using is not going to implode under its own weight due to what I had thought was a large and ever growing size. Apparently what I thought was large was really pretty small potatoes.


It very well could if your software isn't implemented well. The database management system itself, whatever it is (eg., SQL Server, SQLite, etc.), is likely able to handle at least a few hundred gigs of data without problems and is very robust. So I think that the choice of DBMS is irrelevant here.

But if the structure of your database was poorly designed, or if your software is making very complex queries unnecessarily, or if it is trying to read more data than it can handle, then it could eventually come to a grinding halt. These would all be the fault of the software designers, not the database management system which is very robust but still open to inefficient usage.

Since you say that the software is "badly conceived, poorly written, incompetently executed" and that every upgrade "makes things worse", then I'm going to say yes, it is a very real possibility that your system is collapsing under its own weight.