There's a mathmetical measure for "decentralization", you can't tell how exactly centralized it is by looking.
Obviously, to be exact, one would have to calculate a number.
However, it is trivial to observe qualitatively that the network is quite centralized, and this is only the larval form. If a meaningful amount of capital was actually involved, it would be much more centralized.
There is a good analogon in physics. A 3 body problem is just solvable (very hard!) - not a 4 body problem!
And the BFT threshold of 33%
So having 4+ (equally) independent actors is a good start.
And pls lookup Nash Equilibrium