AMD's own RX6500 presentation says it will only be 10-20% faster than the RX580, which is roughly RX590 territory. The 8GB RX580 could be had for $120 or less before the crypto craze flared up for the second time. Since the RX570-590 have roughly twice as much VRAM bandwidth (256bits x 8GT/s vs 64bits x 16-18GT/s), 8GB models have twice as much VRAM and all have a full 3.0x16 interface, I bet there will be many scenarios where the four years old designs will beat the massively crippled RX6500.
The only good thing about the RX6500 is that it will use about half as much power.