Hubble is wavelength limited, not sensitivity limited. Due to the expansion of the universe, and cosmological red shift (as opposed to Doppler) the most distant galaxies are redder than Hubble's instruments can see. The new James Webb Telescope will not produce the awesome color images that Hubble did, but it will be much more sensitive and tuned to much longer wavelengths.
Sorry; but Hubble did NOT create color images; Man did, by post processing the data.
Much like the rain 'colors' one sees on the evening weatherman's little gig.