Wavelength for electromagnetic waves = c/frequency.

So to 'catch' a certain frequency with a receiver the size of the receiver gets proportionally larger as the frequency drops. Focusing light can be done with relatively small gear. Focusing radio waves, especially when the source is distant requires a massive structure and to keep that structure sufficiently cool and structurally rigid is a major challenge. It is already a challenge for the JWST at the current wavelengths, increasing the wavelength while maintaining the sensitivity would create some fairly massive complications.

In the end this is a matter of funding, and JWST already nearly got axed multiple times due to its expense.

I am poking fun (at your expense) at the notion that because the light is already there, adding other sensors would be feasable. Once you grasp the requirements of building an infrared telescope, you will be going, oh!, damn, wow! It's actualy not that deep a dive to get a feel for just how special the JWST is from an engineering perspective, and then a look into just how difficult it will be to get visible light from those distances, which may require a interferometric telescope with multiple huge sub units flying in formation at distances, known to a fraction of the target wave length , but perhaps several hundred thousand km, apart. doable, but :), just