I sense a move 'upmarket' with the new ownership of Morgan.
At the end of the day the traditional separate chassis Morgan must have a sell by date, so even the Plus 4 may be living on borrowed time as far as meeting future safety requirements. I'm sure they see the new Plus 6 chassis as the way forward.
Whilst the CX Chassis is the way forward for Morgan there is no imminent need for the trads to go as they are protected both by Low Volume Exemption and that regulations are not (normally) inflicted on current production models. When it stops it will be because of lack of profit - although regs may be given as the reason i.e. the Defender. (All IMHO of course).