The problem with gold OA is the proliferation of low-quality spam, and the recommended remedy is to both restore exclusivity (raise the barrier to entry) without supporting excessive (monopolistic, exploitative) journal subscription fees. The article's recommendation to build up society journals has a decent chance of accomplishing this. It won't prevent spam from getting published, but the only essential aspect is to keep the spam easily identifiable (e.g., published by MDPI) so it can be safely ignored. The www seems to facilitate the spam business model so I don't think the spam will go away entirely.