Equilibrium is coming.
But that is Ok. Quants can go into material science and model new and useful materials by studying their higher dimensional black hole equivalents [1].
[1] https://www.simonsfoundation.org/features/science-news/signs...
So yields, returns, and inflation are finally stabilizing as the market matures and approaches its "true value"? Nope, because equilibrium is a concept which works well in the natural sciences, but quite erroneous as applied in economics. This is George Soros's argument in his books about the Principle of Reflexivity, which differentiates social systems from natural ones.
What is happening, is merely that trading volume/volatility has tapered off since the '08 crisis. That's expected; empirically, volatility continues to be clustered and autoregressive (a self-exciting process). Its a cycle that will pick up again (one can expect), eventually.
Actually, volatility is only clustered when measured in calendar time. Its much more constant when measured in event/transaction time (plot price against cumulative volume, rather than date/time).
And of course, the answer to your question about which algorithms are working, they are the ones on the opposite side of the trades of the ones that are losing. (Or, alternatively, the ones you can't read about in academic papers or books.)