For a marketplace like Artmajeur, the question isn't one or many SSPs, it's which few SSPs actually move the needle. When we ran a long list of SSPs, we saw classic problems: duplicate bid requests, noisy logs, and CPMs that looked higher but did not lift net revenue once fees were mapped. After we ran a simple SPO audit and cut to three strong partners, our reporting got cleaner, and page latency dropped without hurting fill. In 2026, I think most publishers still need multiple SSPs, but use them like specialist tools, not a big address book one for unique demand, one for tech and tooling strength, and one as a strategic backup. The winning stack is small, transparent, and easy for your AdOps team to explain in one slide.