Ordinarily this is true. What is happening now is that financial institutions are trying to deleverage, so that will soak up a huge amount of deposits without any extra lending at all.
However, if people moved their money from current accounts to savings accounts (which you would expect if people actually wanted to save for the future) then potential lending would increase because banks lend savings cash more readily that current account cash. But people are probably not saving for the future. They are saving because they have less access to credit and/or are worried about losing their job. If anything, that encourages people to liquidate savings accounts rather than increase them, so the potential money banks can lend could be decreasing.