You are absolutely right. Getting started is hard, and I think your point is similar to the Boots Theory. Luckily, the savings that can be had by buying basic staples and eating simply will compound and can be rolled forward into the next grocery trip where you can buy a spice or two.

Unseasoned rice, beans, or pasta is not anyone's ideal meal, but if you're truly in such dire straits that you cannot afford a spice, then the only way to move up is to buy as much bulk staples as you can on each grocery trip. Eventually you'll have enough of the basics that you can skip buying any staples and start buying spices.

Another issue many people have is just buying name-brand, or shopping at convenience-oriented stores. If you shop around, you can often find really good deals. I've also found that shopping at ethnic stores is really good for deals on bulk staples like rice and beans.