This is a grossly skewed perception in respects to those who provide screenshots and participants who express their evaluation and opinion. Vast majority of the time the great releases are highly praised and everyone moves on, whereas poor releases are extensively discussed and heavily debated.
Thus those threads that reprehend shoddy work tend to stand out more than the ones of praise, due to their tendency of brevity, and create a perception that all screenshot evaluation threads solely bash every release.
Much of the debate is protracted by those who cannot see the issues being discussed or outright refuse to acknowledge reality because it falls outside their ideology or rhetoric.
And no BTTF on BR is not a good release, a passable one that many ill informed will enjoy largely due to the placebo of the virtue of simply being on BR.
Universal went the cheap route and they get a Out-Of-Jail-Free card because of misconceptions and distorted information about film; especially with some BS trend being claimed about 80's films. Propagated by the ignorant or by those for whatever reasons will not bite the hand that feeds them review discs.
Aside from that Josh Z did bring a fascinating article that provides some excellent information about digital camera sensors and how many companies are being disingenuous with their specs. Which lies with the lack of any standard for such numbers, similar to bunk dynamic contrast ratios found on TVs.
So what he brought to the table is true, pixel count in of itself does not necessarily mean anything or create better results. Unless it is like the 4K scan system that John Galt praises which is true 4:4:4 color capture. And that system does provide fantastic results.
Anyhow it seems that studios are now using capture systems that are truly 2-8K and we can lay this topic to rest.
In the case of BTTF, again these old 2K transfers were approved years ago by the producer/writer Bob Gale not Zemeckis or the DP Cundey. It is evident that he was fooled by the residual grain left over from the DNR scrubbing which then became more pronounced thanks to EE.
Read the PDF near the bottom, pages 16-18. Film is analog and the amount of detail contained within does not directly correlate to pixels, the point in the digital realm is to a have facsimile that resolves enough information to essentially replicate the analog source. Perceptively 4K is close to the sweet spot for 35mm but 6K is even closer. Perhaps 8K resolves all the resolution available on 35mm but the results of 4K converted down to 2K for home use is excellent.