By weight, a close yes. By volume, hell no. A five pound package of ground sirloin costs at least $20.00. A few quarts of mushrooms runs me about $6.00. Mushrooms are one of those items they either charge a lot for or give them away for almost nothing. They can't be frozen. They only have a shelf life in the store of perhaps five days.
The beef cooks down. The mushrooms do initially but swell up once in the chili sauce in the pot.