Nothing is screwed in my sim, I can fly to Sim-Wings highly detailed EDDH Hamburg scenery, embedded in ORBX Germany North scenery and decorated with AI aircraft and ORBX HD Trees. All that with not more than 6 GB of VRAM useage. If I fly to Sim-Wings EGLL instead, where there's only OpenLC EU and an airport with a bit less detail but a lot more AI aircraft, I get a maximum of 5.5 GB VRAM usage.
So it's all perfectly doable within the constraints of an 8GB card without compromise on settings.
However, I'm aware that there are airport sceneries out there where the developers refuse to do proper texture optimisation, with 4K textures everywhere, including in places where you'll simply never see them. Combine that with other resource-heavy stuff like ORBX TrueEarth and yes I can see how 8GB VRAM can be an issue in such scenarios. So if one avoids using those few unoptimised airports out there, then 8GB cards can work just fine. Is it the preferred option? Of course not, when using P3D v5 in 4K, everyone should have 10GB or more. But there's no reason to buy a low resolution monitor just because one uses an 8GB card. After all, there are also other sims where 8GB works perfectly fine, such as MSFS or DCS.