I know what you mean.
TBH though, referring to it as a "lost art" when you see the general production values of series like Game of Thrones and House of the Dragon is nonsense. These are some of the finest TV shows ever produced, and the lighting is an actual choice rather than a lost art.
I get it. Castles are dark and moody and really didn't have fantastic lighting and the director wants to convey some of that. Some of the contrast lighting scenes in those series are also amazing, when you get a generally dark scene and light flooding through the windows it's incredibly atmospheric.
Part of the problem is though it doesn't work well on standard AV equipment such as the bog standard TVs and also the limited streams that a lot of digital TV services offer which may be in 4K and HDR but lack fidelity due to compression.
If you have HDR it gets better and if you have "scene dynamic" HDR like Dolby Vision it gets better still, where the picture characteristics are actually adjustable on a scene by scene basis. Unfortunately to get these you need a 4K blu ray player, a 4K dolby vision compatible TV (a lot of TVs will have 4K but not so many Dolby Vision unless they are higher end) and to actually purchase the series on 4K blu ray which is not inexpensive. You're probably looking at above £1K on AV equipment to watch this, which is probably not as far as "enthusiast" level but some way above what the ordinary telly watcher wants to splash out, with most people having TVs in the £250-£500 range.
TBH I think they ought to produce two versions, one for the digital streaming services that is adjusted to give better levels and one for the high end AV equipment that can actually cope and give a good experience.
So the TLDR is the moody low level scene lighting looks great if you have the equipment to watch it, and a lot less great if you don't. And most peoples equipment falls into the lot less great catagory.
All of this is a real shame, as GOT and HOD for example are some of the best television ever made (GOT before the last season anyway).