As a cabinet maker and former shop teacher, I understand your distress.
It is a shame that you were not steered to purchasing a mid-century sofa and having it re-upholstered. Not only are most sofas being produced over seas, but the concept of quality has been traded for bottom dollar.
Up to the 1970s one could purchase well built mass fabricated furniture, from American built companies. But with the addiction for low price and American’s desire to push all their kids to college, the two worked hand in hand to eliminate the factories which were providing good quality , at a slightly higher price than cheap.
The money you spent is a reasonable amount to spend on a sofa, it is a shame there is no one able to produce one of quality, as that will eat into the bottom line of the company. Asking a cabinet/furniture shop to produce one, which they will be glad to, but they want to eat and put a roof over their head, so the price is going to be higher. In today’s cut throat world of business there seems not to be anyone who is interested in producing moderately good quality for a moderate price.
Sounds to me like there could be a niche market for some entrepreneur to set up a small factory in Mexico other near by country/protectorate and produce this missing link furniture.