Today we have much tighter engineering tolerances for cost reasons.
Sometimes things are built well or kept around for whatever reason. But most of the time people slap it together and call it good enough. Then when they are done with that item it is discarded.
You can say 'look at all the stuff from the roman era that survived'. You can also say what about all the stuff that didnt? Probably most of it. But you do not see it because it is no longer there.
Surviving Roman infrastructure didn't just sit around for two thousand years, it has actively been maintained in that time.
You'll find that you can keep a lot of grandfather's axes around for as long as you want, as long as you keep them clean, and replace the handle and the blade regularly.