Should you be able to rebuild factories

[OperaticShip743]

Here a survey about it where I propose it more or less the same as here:

[Poll] Would you like to be able to restore important buildings lost in the imperial age? (factories and wonders only if you "deserve" it)

How can we make it viable that destroying them does not lose their value, and at the same time there is the possibility of repairing them? If this can be done it must be under very demanding conditions so that the buildings remain high value military targets. By important buildings I mean wonders and factories. These buildings must be too expensive and too slow to rebuild. :factory:Factories: 6000 wood + 6000 gold To be enabled as a construction cart in the urban center only in the imperia…