Believe me, I’m as much of a proponent of power racks as anyone (today was squat day for me), but that’s not all of the equipment that a person can use that’s good for them. It’s great for the average person to get started, but there are a lot of good exercises (like dips) that can’t really be done on a power rack. Furthermore, a good dumbbell set (that goes up to over 100 lbs) is expensive and takes up a lot of room.
If you need 100 lb+ dumbbells, you're not an average person going to the gym spending $100s per year using the machines. BTW, my power rack has a dip attachment so no extra space needed. The original poster made it sound like you can't effectively equip yourself for the money of a gym membership. True, you need some space, I'm using 10' x 10' in my basement.