Aston Martin thought that they were buying plastic parts from China made to Dupont standards but had to issue a recall when they found that the parts had not been produced to the required standard, and were in fact dangerous, so I wouldn't rely too much on the interpretation of the "standards" or the fact that the tyres are V rated.
Premium tyres are expensive because tyre manufacture is an extremely labour intensive process. Labour costs in China are currently low. It is possible to use automation but the costs are prohibitive and with automation there is a significant problem with flexibility when small batch sizes are required, e.g. tyres in the size required for a +8.
Fortunately we live in a part of the world where there is freedom of choice but, from my point of view, you will always get what you pay for.
Don.