If the feds succeed in passing laws that drive people only to banks for their retirement and investments, what will that mean to the middle class?

I can’t imagine anything like that will ever pass. Plus, banks usually have an investment arm. Maybe the bill isn’t about only being able to get the same interest as savings, but about how secure the investment is? I’d have to see just what laws they are trying to change.

The majority of people with a lot of money and power will not be on board with putting all their retirement money in what would be equivalent to a savings account so I wouldn’t worry much about it.

That isn’t going to happen. Congress won’t pass a law that you can’t get your money managed by Goldman Sachs or Fidelity.

Money in the mattress. Or, more securely, a personal safe or vault.
Unless of course they follow the idea of certain idiots individuals to abolish cash.
Then you would be a truly and utterly fucked slave to the banks.
And do not believe for even one second that it is impossible.
Politicians are all owned by banks and corporations. It may only be a matter of time, and they will sneak it in without telling anybody if they have to.

Rumors are like boogers. Everyone has one. It’s like when I heard (from a car dealer back in the 90’s) that SUV’s or larger vehicles where going to have a special tax added to them at the gas station and it was going to happen soon. Almost 20 year later, and still no special tax or even mention of it.
No doubt, someone mentioned that it would a good way to make banks more solvent and the story blew up to it was going to be a bill passed.
The story probably start with this. http://money.cnn.com/2014/12/12/retirement/pension-cuts/