The performance does scale up with parameters, though it’s not linear.
As discovered by Google in their work on their Chinchilla LLM, performance also scales up with the size of your training set. They were able to do work to define the optimal amount of training for a model of a given size to get the most out of your budget.
So even if we don’t find any better model architectures, which we probably will, if we increase the size of our models, training corpus and budget, we should continue to get more performant models.