the basis of my argument is that the BTC unit cannot be separated from its blockchain (mainchain) w/o breaking Bitcoin as Money. imo, sidechains allow this and if you read their whitepaper, their core assumption is that they they can be separated.
I don't see this assumption. The assumption is that the ledger can be extended. BTC are locked, creating an entry on a subledger. Only by proving the validity of the subledger can the BTC be unlocked. I don't see how this breaks Bitcoin as money.
Blockstream registered as a for-profit entity earlier this year and they have $15M investment. their biz model is constructing SC's for other entities, namely corporations, banks, gvts, anyone willing to pay for the tech. in essence, they are now in the exact same position as Mastercoin, Bitshares, CP in terms of competing to mold Bitcoin into profitability for themselves.
their business model is dependent on inserting a change into the source code called a SPV proof. this would allow BTC to flow off the highly secure Bitcoin blockchain ledger into these SC businesses where sidechain ledgers rules will be determined however the business wants and will be inherently less secure as they will not be merge mined or even directly mined. they will require trust and will ensure security most likely by signing off on blocks as they are constructed with their own signing keys.
Centralized entities have no need for a SPV proof, the federated model using m-of-n bitcoin addresses will work just fine for them. BTW, this is still a SC under the definitions given in the paper, and it can be done today.
there will be thousand of entities who will bolt themselves onto Bitcoin via these SPV proofs. this will in effect allow a siphoning of value, BTC units, out of Bitcoin itself. how will Bitcoin miners make their required income from tx fees if all these BTC have moved offchain to sidechains? how will Bitcoin maintain its monetary function if all these BTC have moved to sidechains and have been converted to all manner of speculative assets?
The only way "all the bitcoin" will move to a sidechain is if the sidechain is obviously better than BTC. If that's the case, why not upgrade? Your BTC will be convertible. I see no losers here.
If "all the bitcoin" move to many sidechains, BTC is still needed as the backbone to move between the different sidechains. That's where the fees will come in, and maintaining a limited block size will ensure they are high enough.
Blockstream has every incentive to encourage this siphoning process. as a for profit beholden to investors, not only do they have an incentive, they have an obligation.
I don't think you understand their business model very well. The have an obligation to profit, yes. But their business is developing new capabilities by extending the Bitcoin platform. In order to continue offering services extending the Bitcoin platform, they have to ensure the Bitcoin platform remains viable. A dairy farmer doesn't eat his cattle.