You apparently still haven't comprehended that for a strict partitioning that obeys the Nash equilibrium, i.e. for transactions that are never allowed to cross-partitions, then the partition doesn't need a separate PoW nor separate block chain. It can be essentially merge-mined (but in the same block chain) without impacting the Nash equilibrium for the block producers. And my other point was that strict partitioning can't exist for scripting yet it can exist for asset transfers (e.g. crypto coin transactions).
I understand perfectly. Under this model, the incentive for block producers is to
exclude partitions from their blocks, because every partition they include increases the chance of their block being orphaned due to double spends. In fact, this is analogous to the problem faced by Iota.
You apparently still haven't understood the point. The blocks are not invalid when a strict partition is invalid.
Of course one might argue that strict partitioning (thus by definition is without cross-partition transactions) is not that flexible. But nevertheless the point remains that there is a design which refutes your assumption.
A strict partition which is invalid serves no purpose that I can see?