"IOW, no ability to project force inland and control the land."
You're confusing ability with need.
There was no need for the Union to project sustained ground forces into Texas.
Do you really doubt that the Union could have easily taken, and held, anywhere it wanted?
The forces the Union sent against Texas were miniscule in comparison to what were directed at truly important Confederate ports.
Mobile was far more heavily defended than any point in Texas during the War, and Union forces didn't have too much trouble not only seizing, but keeping, the harbor, city, and surrounding countryside.
I know this is going to come as a horrific blow to Texas pride, but do you know why the Union didn't much bother with Texas during the war?
Because of its overall unimportance to BOTH the Union and Confederate war efforts.
With the growing Union blockade, Texas ports were less and less functional. And, as I noted, Texas was so far removed, and so poorly connected, that its usefulness as a supply hub for the Confederacy was non existent.
And once the Mississippi River corridor was taken with the fall of Vicksburg, Texas really, as far as Union war plans were concerned, ceased to exist.
