DEF extend life of DPF?

I apologize in advance for not finding the answer already via google or in this vast knowledge-base called an "owner's manual."

Does a DEF system (as in my new 2015 GSW) extend the life of the DPF?

Wrong answer. See below.

But the useof the DEF lets the designers not have to worry about NOX generation during combustion, which does influence what the DPF has to filter.

but the life of the DPF is more about what comes through the exhaust port of the turbo, and what part of it cannot be changed into gas to exit the tailpipe. (this is the accumulated ash)

I would expect a DPF in a 2015 to have fewer issues with cracking and the like, but more do to VW learning more how to manage them than from the use of DEF.

YES!

SCR (Selective Catalytic Reduction: DEF catalyst) allows a more efficient state of tune for the motor i.e. less soot formation during combustion, less EGR reliance etc.

This directly reduces the amount of active regenerations which is destructive to the DPF with enough regeneraton cycles. Yes, driving the engine harder is key to DPF longevity by keeping the temps up naturally (passive region) to the DPF and keeping it in a constant temperature range that allows a slow burn off that reduces soot faster than it is filling the channels.

SCR also allows more opportunity for optimal conditions to the oxidation catalyst (pre-DPF) to oxidize more soot prior to the exhaust gas entry to the DPF channels. So soot loading is reduced prior to the DPF.