It is well known that different lenses often have different filter thread sizes.
Why is this the case? Lens and camera manufacturers have agreed on one (per-brand) standard for attaching the lens to the camera, although the appearance of mirrorless has caused some divergence in the attachment standard. However, there are valid reasons for mirrorless lenses having a different lens mount. I don't see any valid reason for having different filter thread diameters.
It seems to me if the lens diameter at one end is standardized, it could be standardized for most cases in the other end as well. Lenses with smaller filter thread size could very well use a larger filter thread size instead.
The exception to this obviously is lenses that are huge. It doesn't make sense to make the end of every lens huge, so it may be the case that perhaps two or three filter thread diameters would be enough. The smallest filter threads in use currently could be replaced with larger ones.
For example, the Canon 50mm f/1.8 lens could very well use 58mm filter thread to match that of the Canon 85mm f/1.8. Currently the 50mm f/1.8 is using 49mm filter thread.