I think you need to make some better arguments to convince. Your argument only makes sense when wholesale cost of solar panels is significantly cheaper than retail. The better the economics of scale (i.e the smaller the difference between wholesale and retail) the more favourable "DYI" becomes, because the person had home does not need to cover the overheads that are necessary for large scale installations (financing, management, transmission, planning...). It's the same reason that hiring a vps to run all your compute is not necessarily cheaper than buying your own pc.