Wheat gluten (seitan) is protein isolated from wheat flour by rinsing it with water. Wheat gluten is more protein-dense than meat, even beef, while being much more efficient to grow per calorie. So, no, you actually would consume fewer calories of wheat gluten to get the same protein you would from beef.
Remember, it takes 25 calories of cow food (like wheat or soy) to grow one calorie of meat.
You can eat those calories (wheat or soy) directly at 25x more efficiency, and that's just calorie efficiency without looking at water or land use efficiency.
Finally, price doesn't tell you how much it costs to make something nor the financial viability at scale. Just like the price of beef doesn't show you subsidies, the price impact of basic demand, nor externalities.
In a hypothetical world where we switch 100% beef consumption to wheat gluten and tofu, why would it be more costly when we aren't losing 24 calories for every 25 calories we feed to cows anymore?
Even when you wash the starch from wheat flour to isolate wheat gluten, the starch is used as inputs into other foods. When we talk about the energy lost through tropic levels, it's lost as unrecoverable metabolic energy.