The key diving issue is something to be address by the protocol yes, and there were solution discussed previously to encourage the validator to use as less keys as possible. We should try to push forward those idea.
I won’t completely agree with that because the 71 here are validator that receives a foundation delegation, and for those elected they should be elected.
It won’t necessary fix the issue. I have seen in other chains that validators created by the same individual can exist multiple times. This could also happen here. For example, if I am Binance and I control all the delegated funds, I could easily delegate to 5 validators that I am managing.
You can witness what i am talking about here : Subscan | Aggregate Substrate ecological network high-precision Web3 explorer
I would advocate to work on encouraging big validator to use as less key as possible on the protocol level