He was trying to force that on you because it makes him more commission.
Last year when the iPhone 5 was extremely hard to find.. I located 3 of them at Verizon/RadioShack. All of the refused to sell me it at full price ($649). They knew it was a hot item and they wanted as many new activations as possible to boost revenue.
I finally found a Verizon that would sell it outright *IF* I bought $75 worth of accessories with it. I bought the and returned them later that day.
RadioShack gave me a real hassle, to which I contacted Customer Relations and after about 15 emails, my local RadioShack district manager gave me a $50 gift card.
My ATT rep tried so hard to get me on the Next plan when I got my 5s. I finally told him to essentially shut up. When I heard a nearby employee try to convince a different customer to get on the next plan, I said "you guys must get some crazy commission on the next plan." The employee said they get no commission for it. So why are all the reps trying so hard for us to get on the plan?