Originally Posted by
urbanknight
I don't think it has much to do with weight. Rather, it's because it's another part to make and weld on, so it makes the manufacturing process more expensive.
Many bikes its not a weld but simply a threaded hole. We are talking a few cents to couple of bucks on a frame hardly a deal breaker on a $1500 bike. Soma and Surly can put four eyelets in back and four in front,the cost of their frames aren't excessive.