As far as computers are concerned, numbers would have to be astronomical to be even remotely bogged down by them these days. Like, to the tune of a googol. ehhhh maybe not quite that large, but you get my point. Since there isn't one shared online server that everyone connects to (think of games like Eve Online) it would be nothing for the game to monitor everything you ever built over the course of even 1000 hours. It would only be limited by your local computer, since that's where it would all be stored. Factorio does this, in fact, so I know it's way more that possible.