AMD has stopped the production of the Radeon RX 5700, and the GPU has now officially reached the end of its life-cycle. The reference RX 5700 and 5700 XT were already discontinued a while back, but now all third-party variants of the former are no longer being produced, either.

This explains the shortages of the RX 5700 and why the board partner models are presently priced higher than the RX 5700 XT. It’s for the same reason that sales for the Radeon RX 5600 XT grew significantly this month, as it performs more or less the same as the 5700.
Keep in mind that the rest of the 1st Gen Navi graphics cards including the RX 5700 XT, 5600 XT, and 5500 XT are still in production and so are the much older Polaris-based 500-series offerings.
AMD is set to announce its next-gen Navi 2x graphics cards on the 28th of October with a potential launch in November.