The exchange is not quite as important, because those needing to purchase health insurance can go to the federal website. But the refusal to expand Medicaid will leave many poor and low-wage workers without insurance (and therefore without adequate access to medical care) -- somewhere between 1.5 million and 2 million Texans. This is inexcusable, since the federal government will foot the entire bill for 10 years and then continue to pay 90% of expansion costs after that.
The Republican leadership would like for Texans to believe they are saving them money by refusing to expand Medicaid. That is a lie. As the chart above (from the Commonwealth Fund) shows, Texans will still be paying the money (taxes, fees, etc.) to fund the expansion, they will just not be getting the benefits. Instead, because of the intransigence of the Texas GOP, other states will be getting that money, low-wage workers (and their families) will have to continue to go without any health insurance.
The Republicans claim to be the party of "fiscal responsibility", but they certainly aren't acting in a fiscally responsible way this time. Not only are they passing up the $9.8 billion dollars being offered by the federal government, but they will also be passing up all the economic good that money could do as it circulated through the state economy -- creating several times that amount in new spending, enhancing profits and creating new jobs as it increases demand.
The problem is that the state is not being run by old-style business-oriented Republicans, but by ultra-right-wing teabagger Republicans -- who consider their ideology more important than fixing the economy or saving the lives of Texans.