the thing is
something isn't available --> you get something better = ok (instead of previous goods current goods)
something isn't available --> you get something worse = not ok (current age goods are worse than next age goods)
let's say you order an Iphone 11:
you get Iphone 12 for the same prize --> you are happy
you get Iphone 10 --> you complain
Order can be made when the product is available. Here, game is taking care that approach automatically since no next age available and gave current age goods as a choice until next age become available.
Let's assume, due to some technical issue space age Titan takes 2 years time to deliver. In that case, game inventory will have many "next age goods" items in a sleeping state, since it can't be opened or no use. Instead of this, it is made to give something useful to you for current age purpose. This is specific to people who are in the last age.
As you mentioned in the idea,
it can't be open until that age is released with the tooltip saying that
making a change to keep something idle is worse than receiving current age goods.
Problems in the approach,
1) 80 space age Titan goods, on what classification, Is it always 16x5 goods of new age or 80 of anyone good or 40 of two goods? You keep the item in the inventory, how the game decides the classification before age released, easy choice is 16x5 but event results coming like one particular good reward as 80 count. So each item in the inventory, whenever player opens, it should pick the good automatically or player should choose which one good they need 80. For one reward, this much process, if they implement, I will be more happy to use it.
2)
whenever one age released, next age will be shown as disabled, so as per this idea, inventory item always shows that tooltip. Players cannot open it, for example "Space Age Titan released" and "Space Age Callisto or Space Age Europa" got disabled means, no chance of opening it.
3) inventory keeps the item and next upcoming age registered to that item is the possibility. Why to register with something not available completely. You can guess the baby name before birth but without birth you cannot get the birth certificate.
