I'm not sure of your business acumen but it's always a cost/benefit thing (Google Ford Pinto memo if you're curious; its truthfulness is suspect but it's the most blatant example of what I'm trying to get at). In Rome's case, it's probably the case that it's cheaper for them to deal with customer complaints and send replacement parts than it is to invest in processes to ensure it doesn't happen in the first place, at least in the near-term.
Of course, this is purely an economic scenario. You can argue that if they just build superior products, then they'll have stronger legs to stand on and attract more customers so that investment might actually be worth it. But I'm not well-versed in their board room meetings enough to know what went into this decision, or if there was ever any discussion at all.
TL;DR - Investing in manufacturing processes to eliminate defects is not always cheaper than just dealing with the defects as they come.
I am fairly well-versed in the trade-offs some companies make to ensure profit margins are sustained in manufacturing. But there comes a tipping point where inferior design / materials becomes a risk to overall brand value if/when enough customers perceive quality of a product to be inferior due to continually having to contact customer service due to early breakdown of parts etc. Especially if the cost of the product to begin with warrants a higher level of quality in the eyes of the consumer. That applies not only to Rome, but all companies.