While investment and savings aren't opposites, they also aren't guaranteed to be linked, at least if by investment you mean "increase in productive capacity" rather than an accounting identity in some macroeconomic models.

Increasing a bank's ability to lend doesn't mean they will necessarily do it; the reserve ratio is an upper bound.

Also, even when they do make a loan, it also doesn't mean it will necessarily go towards building or improving productive assets. Sometimes loans go towards buying existing assets (such as houses) in a way that might just result in asset inflation. (As in, for example, stock buybacks.)

The idea of a "global savings glut" is somewhat controversial but not obviously nonsense. We can't learn anything by defining it away.