Mixing full nodes and SPV clients in one diagram is like mixing web servers and browsers in one diagram. It just makes no sense.
Full nodes act as servers. SPV wallets are clients that need a full node to connect to and they do not act as a server. As most SPV clients connect to a random node of the network, I have no clue how all those SPV clients out there will ever get in contact with the future 2x blocks. The overwhelming majority of the full nodes will not accept and serve them.