One of the “equivalents” will be launched in a few years as the Nancy Grace Roman Space Telescope (formerly WFIRST). It isn’t quite an equivalent: it was design

One of the “equivalents” will be launched in a few years as the Nancy Grace Roman Space Telescope (formerly WFIRST). It isn’t quite an equivalent: it was designed to image the Earth, not distant objects. It has a wider field of view than Hubble, but is less useful for imaging distant galaxies and exoplanets in detail. Unfortunately it also doesn’t deliver the expected cost savings, since the telescopes came without instruments or electronics. Different people at NASA made different estimates, but most showed the NRO telescope as being roughly a wash compared to the earlier WFIRST concept, and it has overrun its cost substantially since then.