Fundamentally, Millennials have been shaped by consumer culture in ways that previous generations have not.

Sure, but it's a big leap from there to:

That means that the response to the Church is primarily consumerist

I don't see any rationale to support the idea that millenials are approaching the Episcopal Church (or any church) out of a consumerist mindset.

The desire for authenticity or identity is not inherently consumerist. Rather, consumerism consists a false solution to the search for authenticity and identity. As a Christian, I think it's difficult to make the case that Christianity is a false solution to these problems.

You point to the solution being false because you think it provides a false nostalgia and a poor community, but I don't think this argument holds much water. I don't see any reason to think that anyone's main reason for going to a specific church is because it makes them feel a false nostalgia, and I've seen nothing but an incredibly warm community in TEC. Granted, that last one varies from parish to parish, but that's why it really shouldn't be considered a fair criticism.

Basically, what I'm saying is: I don't buy the idea that millenials are approaching TEC church from a consumerist mindset. The only example I've seen like this are 1.) Evangelical megachurches, not TEC, and 2.) aimed more at older generations then millenials.

Honestly, I'd argue that part of the appeal of mainline churches is that they aren't as focused on their brand as a lot of Evangelical churches are. That's probably pretty specific to my background where there where a ton of nondistinct Evangelical megachurches having turf wars to see who was the hippest place to be, but I've never seen anything like that from mainline churches or the TEC.