I make my name simpler, and people still can't get it right!
Oaktree,
From my experience with Excel & Access, I would say that only a very small minority of Access applications are built directly because of Excel's row limitation. So I think it would have a rather small impact on Access.
Most Access applications are built in Access simply because Access is better equipped to handle the task at hand. As matter of fact, I often see Excel questions posted on this board that would be much better handled in Access, but I rarely see the opposite (Access questions which would be better handled in Excel).
I would also say that if you have more than 65,536 rows of data, Excel may not be your best bet anyway! I am very interested to see what kind of performance these huge spreadsheets will have in Excel.
In case it sounds like I have an Access bias, rest assured that I do not. Excel is my favorite program and I prefer it to Access. But I work a lot with relational databases, and Access is quite simply better equipped for those sort of tasks then Excel.