Those are great - and in terms of level of quality you can really tell where time went in. That work probably involved modeling in things like draft/part lines, weathering on the details, stitching etc. Those are things that often a complete remodel of the 3D usually in a traditional animation package, custom shaders to match the leather grain, etc.
Without the OP’s types of products hard to say who’s right or wrong. More importantly, if a $20k render will actually sell more product. I would argue @ 20K you might be better off building appearance models and paying a professional photographer depending on the type of product.