As in the threads I linked in my previous post, "the present form + ものだ" means "ought to" or "is expected to be the case", whereas "past form + ものだ" is for past habit "used to". They are not interchangeable. As for your example sentence, これ is the key. These ~ものだ have a nuance of "generally speaking", so they are not used for a specific thing such like これ. If the topic is thing(s) they make repeatedly/customarily, e.g. こういうもの, it would be able to mean "used to".
In conclusion, もの is the pronoun for これ, as in the second interpretation in your initial post.