I think your core premise is flawed.

It seems to me that most in the community want Bitcoin to be a good form of money - and a good form of money is BOTH widely accepted / fungible / divisible / easily transferable ("everyday currency" features) AND durable / price-stable ("good store of wealth" features).

The two general quality sets are not mutually exclusive and a refined Bitcoin implementation can arguably do both with no need for running two blockchains.

I also think that you're confusing the investment function with the monetary function - which is to be a store of value / accumulated wealth.  The investment function is not about storing wealth.  You invest to increase wealth, and you take risk to do that.  The whole point of investment is taking risk and thereby capturing the return which is commensurate with the level of risk that you're taking.  If you simply want to store your wealth (accumulated value / excess productivity) then you don't actually want to take risk, you want stability of value.

Most current forms of "money" are poor stores of wealth because they have a near-zero marginal cost of production and will therefore be produced until they have no value - which is to say that they only become price-stable at near zero.  The point of central banking is to control that production via cartelization, but ultimately central banks can only really delay the endgame of the market value of the currency declining to its marginal cost of production.

Bitcoin potentially solves the "store of wealth" problem by having a significant marginal cost of production built into its protocol.  And if it can manage to become widely accepted then its volatility (risk) will decline substantially and it will cease to be a good/bad speculative investment vehicle leaving the door open for it to become a very good store of value.  The issue remains as to how it can solve its own "everyday currency" problems (in the specific BP101 case - easy transfer-ability) and that's what the current debate over block size is about.  Folks have different opinions about how transfer-ability might be threatened by either:

1. Large block sizes and the bandwith required to process them (and how that effects decentralization which might potentially effect transfer-ability) and...
2. The ability of the current protocol and fee structure to manage a large overflow of unconfirmed transactions in the Mem Pools of the various network servers.

Personally I have some non-trivial concerns about 1 and absolutely no faith in 2 so kicking the can down the road by increasing block size A LITTLE while the community develops a better long-term solution makes sense to me.  The problem with XT is that it increases the block size a LOT (thereby substantially increasing the risk of issue 1) and does nothing to solve the bandwidth/decentralization problem that will (hopefully) eventually affect XT as well.  It would seem that the proponents of XT either believe that cheaply available bandwidth will outpace the growth of Bitcoin over the intermediate term or that they don't really share the same concerns about centralization of payment processing that I and a lot of the community do.  

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