So I think perhaps we are talking past each other. In particular, my definition of reductionism is that we can understand and model complex behavior by breaking a problem in to its constituent components and studying them in isolation. i.e. if you understand the micro-hamiltonian and the fundamental particles well, you understand everything. The idea of 'emergence' as physicists understand it (and as Laughlin was using it), is that there are aggregate behaviors that cannot be understood from looking at the individual constituents in isolation.

A weaker version of reductionism would say that to make absolutely accurate predictions to some arbitrary scale we MUST know the microphysics. Renormalization arguments ruin this version of reductionism.

In a sense this

if you wanted to know with 100% accuracy where the shell was going to land, you would have to go further down than this.

seems to be espousing this form of reductionism, which I strongly disagree with. There exist physical theories where knowing microphysics is irrelevant to arbitrarily accurate predictions. Perhaps it would be best to agree on definitions before we make points irrelevant to each other.