The M240's EVF is outdated technology, years behind the times and outdated from day 1 of the M240 -
I just love these sweeping statements. The VF-2 was introduced with the Olympus E-P2 in Nov 2009, the VF-4 used the new hardware announced by Epson as of June 2013. The M typ 240 was announce in 2012, and became more readily available in early 2013. So the VF-2 is
at most three years longer in production than the M typ 240. It remained the
state of the art EVF on the market until the VF-4, which was released AFTER the M type 240 was already at the point of final hardware development.
I have both the Olympus VF-2 and VF-4. Used on the E-PL1 with a firmware update for compatibility, they render exactly the same since the E-PL1's hardware cannot support the VF-4s higher resolution mode of operation. Used on the E-PL7, the VF-4 is superior but by how much is a matter of opinion. To my eye, they are much the same; the VF-2 is/was an excellent EVF unit.
The M typ 240 video hardware that drives the LCD and EVF has to deal with more pixels from a larger sensor. I suspect there are simply hardware limitations in the M that make it difficult to drive it as well as the E-PL1 or E-PL7, and prevent providing compatibility to the VF-4. I suspect also that there would be little significant improvement if they could update to VF-4 compatibility for the same reason.
The later Visoflex type 2 EVF from the T (also X) is an improvement over the VF-2 generation like the VF-4. (I believe it uses the same Epson hardware.) How much improvement is again a matter of opinion; since I can compare them side by side, I have to say it's not by any quantum leap. The Leica X drives it well, it is useful.
I suspect Leica will use the Visoflex type 2 in the next iteration of the M but it can't be backwards compatible with the VF-2 since it uses a new (and more secure/cleaner design) hardware interface to the camera body, and it will imply a rather large improvement in the M video supporting hardware to get the most out of it as well.
Of course, the M typ 240 will continue to be just as useful as it is now even when the M typ 240+n goes on the market...
G