The thing is? He totally could. He stands without holding onto things to play all. the. time.
He actually took 5 steps to me yesterday, but I don't think he realized he did it because he was crying and wanted me to pick him up. Here's more proof: Have you every tried one of these strollers? They're more unstable than a Maclaren with a diaper bag on the bag. Yet he walks behind it no problem.
I recently bought him squeaky sandals from ThredUp for $4.50. (ThredUp is pretty sweet online consignment shop, use this link for $10 off your first purchase.) He does seem to really like hearing the squeak, so hopefully those help motivate him. (At home. I won't put other people through that squeak noise.)