Spam will come and go in waves, like other traffic and like it has done before. Keeping non monetary crap out of the blockchain will reduce permanently stored bloat, reduce the bandwidth needed to IBD and stay synched and reduce CPU/ram resources for verification. If we keep the option of running a full node accessible to as many people on the planet as possible this will keep bitcoin accessible as money for them as well. Do you think bitcoins future should be money in the hands of the many, or a d!c#pic playground for the first world?