If you assume that accelerator technology remains the same then you do of course have to keep making your accelerators bigger. There are a fairly large number of people working on plasma accelerators which are more compact because they support a greater accelerating potential. The AWAKE experiment [1] is an example of such a project.

As an aside, I think this is a great example of a role which fundamental science plays in society: It can facilitate step changes in technological progress.

[1] - https://en.wikipedia.org/wiki/AWAKE