I can't listen to music with vocals at work, but I still listen to power metal 20 years later in quite a few contexts - gym, car, walk, simply active listening. I can't argue with the quality of the lyrics being cringey though.
I've always thought it's a combination of the genre being niche and being founded on a set of lyrical themes that are restrictive - and maybe particularly challenging -, and also, the fact that a lot of these bands aren't from English-speaking countries. The bands from anglo countries like Kamelot tend to write acceptable lyrics within the power metal context (Manowar lyrics are hilarious at times and arguably well-written, but they are not power metal IMO). There are some noteable exceptions to non-anglo bands with polished lyrics, like perhaps Nightwish or Blind Guardian, but a common occurrence otherwise is to find shitty English, which at least for me is an instant turnoff.
I can imagine some lyrics can be hard to listen to for an english speaking native. Manowar made a german version of "Heart of steal" it's called "Herz aus Stahl" it's so bad when I heard it for the first time I thought "Oh man I hope we don't sound that bad to all the people who speak english when we're singing english."
I don't know if it's that bad... In my experience the English lyrics from these euro power metal bands are ~98% good, but then there's the odd line that has you reach for a thesaurus to see if that's real English or they've pulled it out of their butts, and most of the time it's the latter. It's pretty off-putting, it would be perfectly OK if that was it, but it often brings your attention to the fact that the lyrics are very weak in general.
FWIW, Kreator, Scorpions, Destruction, Sodom, and basically every other German metal band probably have better English than most native speaker groups for the past 40+ years. Americans in particular seem to do quite poorly at speaking other languages partly because to be American, particularly in cities, one needs to know several dialects given the many different creoles and vernacular groups due to the country being so massive and diverse.
Interestingly enough, I believe while Kamelot was founded in the US, most of the members are from Europe currently.
One thing I learned ~15 years ago was that Nightwish commissioned lyrics from lyricists (one such commissioned person told me himself I believe a year or two after Dark Passion Play was released - they never used what he wrote for them though) - maybe that helps give the polished impression for some.
I've always thought it's a combination of the genre being niche and being founded on a set of lyrical themes that are restrictive - and maybe particularly challenging -, and also, the fact that a lot of these bands aren't from English-speaking countries. The bands from anglo countries like Kamelot tend to write acceptable lyrics within the power metal context (Manowar lyrics are hilarious at times and arguably well-written, but they are not power metal IMO). There are some noteable exceptions to non-anglo bands with polished lyrics, like perhaps Nightwish or Blind Guardian, but a common occurrence otherwise is to find shitty English, which at least for me is an instant turnoff.