Strongly disagree here
For the vast majority of users, a 12th-14th gen at a great price point would be an excellent build(Same for AM4 build). Just because the platform is "dead end" is of little value importance to the majority. I Personally ran a Ivy bridge from 2012 till 2019 until I upgraded to a 9900KF(Grateful I skipped8th gen...). I went through many GPUs but the platform was more than serviceable and still is living on as a plex server out in the wild.
The biggest upgrades in the future are going to be a better GPU and perhaps an add in AI NPU to add TOPS if AI actually does become a "killer feature" rather than an intrusive annoyance. CPU and DRAM speeds are well passed diminishing returns in terms of ROI in performance uplift for your dollar. This deadend logic for CPU upgrade on a mobo is makes no little sense in practice. 8-16 Cores is more than capable for the long haul. If you need better encoding, get a hardware dedicated encoder. If you need TOPs, grab an accelerator[GPU or dedicated]. These platforms come with PCIe gen 4 or 5, might wish for more lanes in the future, but I'd wager that CPU is not going to ever be your bottleneck(and if it is, you should like use dedicated silicon for that task [accelerator].
As many have already pointed out, you are not limited to 14th gen, 12 + 13 offer great value and on the used market you have many better options than the 14400 as well as on the AMD side. I'm sitting on a 13900 and doing my best to not waste a hundred quid to side upgrade to a zero uplift 14900(Hey but I would get APO??? would love an update on that). Arrowlake or whatever is coming next for the desktop can't come out soon enough. I'll also grab a discounted Arc if it ever comes down to bargain prices, battlemage might do the trick