To be fair, Austrian have had MAN-VIE pencilled back in, on and off for years but never acted. Therefore it is a credit to Jet2 to see the numbers of pax from MAN going to VIE and putting a service on. I am sure this act alone has prompted Austrian to come off the fence - even now, nothing is official.
I remember the Austrian MD80s being full & then the twice daily CRJ Lauda Airs being full- they chose to abandon the route.
There is a leisure market ideal for Jet 2 & a Star Alliance consolidation of interline routes from MAN. Most of the interline destinations from VIE are already covered by LH via FRA & MUC, so any increase in connections via VIE maybe at a cost of reductions on the high cost Lufthansa routes. Lufthansa's ethos is to reduce short haul flying right through Europe in favour of third party Star Alliance carriers.
I'd be careful what you wish for.