I would figure the opposite. There are plenty of people like me staying on AM4 because of the RAM price increases. I will probably skip AM5 entirely.
(Ignore my AM5 workstation with 192GB RAM in the corner)
Considering PC desktops. DDR4 is 3200 MT/s max JEDEC. DDR5 is available on AMD since 3 years and is 5600. DDR6 specification is almost finished. It looks like DDR5 will double performance just right before new DDR6 DIMMs appear. Thus I'd expect DDR6 to double the bandwidth just as late when the new memory standard arrives.
Strange, I bought 64GB DDR5 6400MHz last year and apparently my motherboard can handle up to 7200MHz (or more with overclocking).
Intel's desktop CPUs from last year support up to 5600 MT/s with regular DDR5 DIMMs, or 6400 MT/s for CUDIMMs. Speeds higher than this are achievable, but are overclocking.
If your memory modules are rated for 6400 MT/s, they are most likely advertising the speed when using an Intel XMP or AMD EXPO profile to overclock the memory (and the CPU's memory controller). The JEDEC standard profile likely is no faster than 5600 MT/s. It's also possible that you bought last year a kit of CUDIMMs rated for 6400 MT/s without overclocking, brand new to the market at that time, and of no help whatsoever with any CPU that isn't an Intel Arrow Lake.
The singaling is double the transfers but the bandwidth does not double.
We've seen what ... 5 ... itterations now and people still get this wrong.
The doubling of transfers comes at the cost of latency and processing overhead, always, until the new standard matures and might match the predecessor latency.
Did dual channel DDR5 double dual channel DDR4 bandwidth? Short answer ... nope, not even close, and DDR4 4000 remains viable and trades blows with DDR5 to this day in application performance despite "losing" in sulunthetics.
In fact my wife is still rocking that machine - although her gaming needs are much less equipment intense than mine. After a small refurb I gave it (new case, new air cooler, new PSU) - I expect it to last another 5 years for her.
My new one is a 9700X. Didn't feel the need to spring for higher power budget for a marginal gaming performance bump. But I suppose that also means it's much more practical for me to jump to a newer CPU later.
It's faster than the prior machine, but it sure does not feel like it does things the previous one didn't
I think it's very telling so many people upgrading now are coming from Haswell chips, they are a legendary chip generation, and arguably the last time anyone needed a CPU upgrade short of operating system support or warranty concerns.
Notably, Haswell makes the cut for Win11.
Not that I'd use that over Linux. (I run Arch, btw)
It makes the cut for something else, x86-64v3.
Which I thought was the baseline for Win11. Apparently, not the case.
I'm a gamer, often playing games that need a BEEFY CPU, like MS Flight Simulator. My upgrade from an i9-9900K to a Ryzen 9800X3D was noticeable.
6000 C28 at 256GB using 4x64 is not at all on the bandwidth high end these days, but it's way more than DDR4 could provide.
Most boards support 4x64 at 5600+ now, some go to 6400 with it if you tune voltages and terminations. .