Steve is an enormous 6-4 305 lbs. Have you ever stood beside a man that large?
I've stood next to Steve and yes he's a big dude but I wouldn't classify him as enormous. I see that NFL.com has him listed now at 305 but last year he said his playing weight was around 295. Maybe he's added some weight. He'll need it if he wants to survive against guys like Henderson and Stroud. Most centers in the league are around 300. They are usually the "lightest" guys on the line.
I stood next to Lincoln Kennedy once. I think he's something like 6'7" 335 (or at least he was at the time). This was back when o-linemen over 300 was still something of a rarity. At the time, I thought that was enormous.
I don't think the Texans offensive line is extrordinarily "massive." I'm sure most NFL teams probably average well over "3 bills" now across the front. They do have some tall bookends when you consider Wand and Wade.
Bulk isn't everything (unless you're a nose tackle I guess). There are some huge (330+) guys out there. I watched Tarik Glenn pretty close in Week 17 last year and he's so fat .....[fill in the punchline]. Flozell and the current version of Larry Allen come to mind. Give me a bunch of strong, agile 305-310 pounders over a bunch of strong but immobile fat guys any day.