While it would be nice to increase the number to show your shop has had more individual item sales, I think it seems more accurate the way it currently is. If a customer is buying 2 items at once, it still is 1 order, so I would think of it as 1 sale.
I have another business selling hair dye on my own website (not etsy) and if someone buys 3 bottles of hair dye, the shopping cart software is going to count that as 1 sale. it makes sense. When I enter an order into quickbooks, it is counted as 1 sale, not an individual sale receipt for each item purchased by the same customer, you know? So why should it be different on etsy?