TL;DR: Purchasing a Ryzen 5000 processor or an RTX 3000-series graphics card right now is akin to getting an audience with the pope, but there is a way to grab the latest Nvidia GPUs and, eventually, the new AMD CPUs: buy a pre-built Corsair a7200 series PC.
Despite both companies' best efforts, the RTX 3000 and Ryzen 5000 parts have been plagued by availability issues since launch, partly due to scalpers snapping them up in bulk and reselling the hardware on eBay for inflated prices.
The good news for those looking to upgrade their aging, potato-like PCs is that Corsair's new Vengeance a7200 can be configured with a Ryzen 7 5800 X, Ryzen 9 5900X, or Intel's Core i9-10850K along with an RTX 3090, RTX 3080, or RTX 3070.
Sadly, it seems even Corsair can't secure a Ryzen 5000 processor at the moment. The only configurations currently available consist of Intel's chip paired with an RTX 3080 or RTX 3090. The former comes with 32GB of DDR4 3200, a 1TB M.2 NVMe SSD + 2TB HDD, and Windows 10 Home, and is priced at $2,800. While the latter ups the memory to 64GB of DDR4 3200, has two 2TB M.2 NVMe SSDs, and Windows 10 Pro, pushing the price to a hefty $4,500.
Buyers also get a Z490 motherboard, a 4000D Airflow mid-tower case, and an H100i RGB Platinum all-in-one liquid cooler.
While it's a shame that the Ryzen 5000 CPUs aren't currently available, this is at least one, admittedly expensive, way to own an RTX 3080/3090 without putting money in the hands of scalpers.