Not sure I agree with you overall, but I do agree with the distinction between computational power and I/O (or capabilities). That's a very important design criteria for languages for distributed systems.
I think the problem would be that the computation would get cut off at different points on every machine, leading to an unstable ecosystem. Remember the browser has to run on devices with at least an order of magnitude difference in resources, probably 2 orders now.
Generally, you want to guarantee that your style computations terminate. Now it appears that CSS doesn't actually provide that guarantee, since it's Turing complete :) But I guess it's close enough in practice.
I think the problem would be that the computation would get cut off at different points on every machine, leading to an unstable ecosystem. Remember the browser has to run on devices with at least an order of magnitude difference in resources, probably 2 orders now.
Generally, you want to guarantee that your style computations terminate. Now it appears that CSS doesn't actually provide that guarantee, since it's Turing complete :) But I guess it's close enough in practice.