Since the recent (2019) mathematical discovery allowing elimination of spherical aberration[1], I've wondered if lenses will either be simplified, or redesigned for better optical performance.
Sub-µm accuracy is not at all easy for a CNC mill and the surface quality is way to bad for optics.
Commercial aspheres are polished with special CNC grinders, but achieve nowhere near the quality of spherical lenses. Only recently magnetorheological finishing became available which allows getting a bit closer in quality.
In most applications, it makes more sense to stack a few spherical lenses instead of manufacturing a super expensive custom asphere which cannot even compensate for chromatic aberrations.
[1] https://arxiv.org/abs/1811.03792