You never know who is a Keystone until they're gone. From London Fletcher to Roger Saffold people make decisions based on projections and those projections can be wrong.
Obviously, Holmes was highly thought of and the question becomes was he the guy or was he benefiting from the guy or was it a chemistry between all the guys that must stay together to perform at high levels.
I do think McVay and actually Sneed as well are visionaries. They anticipate and are making long-term moves to go with their short term splash plays so ultimately I think they've got it covered but obviously you can't be sure and that's why I am a bit worried