Substance 3D is licensed as a collection of tools, sold per seat to the 3D and design teams who texture, model and render. Adobe offers it as a standalone collection plan or folds it into a broader Creative Cloud enterprise agreement.
Because the user base is specialist and the line item is small relative to the main Creative Cloud spend, the seat count is rarely scrutinised. Seats get provisioned for a project and stay assigned long after the work ships.
When Substance is bundled into a larger enterprise deal, its cost becomes invisible. That suits Adobe at renewal, because a line you cannot see is a line you cannot push back on.