My previous post was deleted, so I'll Re:
If you need explanation for that, you are slow.
I bought the 5600X at a BF deal for $240 (not $300) and sold my 3600 for $175. I don't need a new motherboard, I have a great B450 which has seen me thru Ryzen 2600 to 3600 to 5600X and I'll have the option to upgrade to Zen3D too, something intel users will never have.
That means I ended up paying $75 for the 5600X upgrade. That = cheap. Get it?
It will be the same (a cheap upgrade) when/if I decide to upgrade 5800X3D, much cheaper than buying a whole new intel system.
Also you're flawed reasoning is based on a comparison of Zen3 prices with the 10th gen intel platform which is 2 years old now, I'm pretty sure you can also buy a 2 year old Zen2 platform cheaper than the Zen3 one.... imagine that discovery.