CCP have spent a lot of time and effort recently trying to improve the economy and industries part in it .
My solution would be this .
Have all the NPC entities ( Empires, Concord, Rats, Corporations ) account for every ship they lose. Then have the entities buy those ships , modules etc. (or a percentage of depending on the math of whole of new eden) representing the fact player industry is supposed to be a major part of the overall percentage of industry in new eden .
This could be achieved by having them ‘buying’ sell orders as replacements from the nearest major marketing hub of the region ( these may need to be assigned constellation by constellation ) .
So what do mega corps themselves do then might be a point against this idea . I would say they are responsible for the food warmth and shelter of there employees , they are also primarily invovled in BPO production and research and development of new technologies and advances in technologies we already posses .
They hire us to do there security, logistics, etc. so why not have them actually use a percentage of the playerbases industry output as well .
This would take time in development , I understand , but it would create a more realistic economy for industrialists to work in .
A true player created industry . It might even effect how powerful each group becomes over time . That in a later iteration they might have NPC entities might have ‘budgets’ and ‘incomes’ and become more powerful or weaker as they buy and lose equipment . Like really playing against AI factions that can be ground down or allowed to florish depending on player action and industry