Thought I'd be the smart ass that said "but a protein kinase 's expression level says nothing about its activity" BAM, Kinome sequencing exists! Why did noone tell me this existed😆

I do not see the conflict between your statement and the poster? They have plotted the expression level of various kinases - it is still solely a transcriptomic readout. Except for alternative splicing, which affects the substrate preference of some, you do not get direct information on their targets. For that, you still need something like mass spectrometry-based phosphoproteomics or antibody-based proteomic assays.

So that is actually an antibody based assay for all known kinases and all their known states. It actually tells you the ground truth of phosphorylation rather than expression