Prediction: in a few years we’ll increase the Bitcoin block size.

If the reactions to pegged sidechains are so hostile and almost nobody wants to break the 21 million supply cap to pay the miners, we’ll conclude that turning the 1 MB into a 4, 8, 16 or whatever isn’t that bad because at least we understand the tradeoffs and there is no extra complexity involved.

As @peterktodd put it: it’s cheaper to increase the computation costs than to increase the degree of human politics.