Only within the last year have Sony, Nikon, and Canon released their flagship mirrorless cameras (the Alpha 1, Z9, and R3 respectively, though the R3 might be s

Only within the last year have Sony, Nikon, and Canon released their flagship mirrorless cameras (the Alpha 1, Z9, and R3 respectively, though the R3 might be semi-flagship if R1 becomes a thing). From what I gather, before this generation of "stacked" sensors there would have been too much warbling from the rolling shutter to be truly useful for things like sports photography. So most sports stuff is probably still shot with DSLRs, but that will likely change in the coming years, as (a) mirrorless cameras can ostensibly shoot more quickly (b) photographers replacing their gear won't have much of a choice.