No they don't. Their actions have proven that over the last 1-2 years.
Ok, I understand , You are one of those conspiracy theorists without evidence who doesn't take either their word or work in support of raising the capacity as any indication... Big, old bad Blockstream(never mind the other 40 devs) out to eat your children and all... Gotcha.
I'll preface by saying that the Blockstream guys are highly competent coders and cryptographers, they were before they formed Blockstream, and they are today. Your placement of trust in them thus far is not alien to me. However, a conflict of interest is an insidious thing, it may start out benign, but under the pressure of investors, deadlines, and runway... may begin to allow a form of self delusion... a self reinforcing mentality that what is best for the company is best for the protocol.
The investors that deposited $21 mil didn't do so out of charity, they were sold an eventual ROI. I'm not satisfied with the thesis that it was "we're going to altruistically contribute open source code to better Bitcoin, which will probably make us massive amounts of money somehow, and we'll dissolve the company while stiffing the investors if we have second thoughts about it." I want to know how they plan to make money, and if artificially crippling the main chain could incubate that plan.
It seems that more distribution of available software is the only way to allow miners, who issue the votes that count, to fully exercise their built in right of voting with hashes. If the miners continue to choose core's direction, so be it, I'll convert my node to a segwit node so it actually continues to fully verify. I got interested in Bitcoin because it felt like there wasn't a central point of control, that it natively resisted control by centralized influence. I have confidence that the market will settle the blocksize just as efficiently as it sets the price and the difficulty, a market with production quotas is not a market. Mining valid blocks is not a trivial thing, and those doing it have an interest in seeing the system they manage be as successful as possible.