I would suggest that production companies should interpret JRRT's works as they are into film and streaming *without* "improving" or doing an "update for modern audiences."
Tolkien's works, AS THEY ARE, have sold 600 MILLION copies in x87 languages.
Gee, if we only had a way of testing the potential success for Middle Earth stuff that tries to stay true to JRRT's writings, or when the production goes off on its own…oh wait, we do!!
We have a real-world market test -- two movie series produced by the same guy, eliminating a difference in producers as a factor in outcome.
1. Sample A – LOTR Trilogy by Peter Jackson tried to stay as true to JRRT's books as practical, with some creative license. Some of the top grossing films of all time, widely acclaimed. P/E ratio is about 10:1 – cost $300 USDM to film, earned~$3 Billion.
2. Sample B – Hobbit Trilogy by Peter Jackson deviated broadly from JRRT's book, with much creative license to "improve" on JRRT's story with new characters and content. Made lots of cash, but not at the same ratio as LOTR, widely mocked by fans. P/E ratio is about 4:1 – cost almost $800 USDM to film, earned ~$3 Billion.
Metacritic reviews rank the films based on year of release:
1. LOTR Return of the King – 94 rating, ranked #1 for the 2003 release year
2. LOTR Fellowship of the Ring – 92 rating, ranked #2 for the 2001 release year
3. LOTR The Two Towers – 87 rating, ranked #6 for the 2002 release year
4. Hobbit The Desolation of Smaug – 66 rating, ranked #201 for the 2012 release year
5. Hobbit Battle of Five Armies – 59 rating, ranked #308 for the 2014 release year
6. Hobbit – Unexpected Journey – 58 rating, ranked #298 for the 2012 release year
Results:
*Each of the LOTR movies were among the top-rated movies in their release years and earned 10x.
*The LOTR movies won some 475 film awards across the Trilogy, including x4 Oscars (Best Cinematography, Best Make-up, Best Visual Effects, Best Original Film Score).
*Each of Hobbit movies were among the most poorly rated movies in their release years and earned just 3x-4x.
*The Hobbit movies earned just 43 film awards across the Trilogy, including one Oscar (Best Scientific & Technical Advancement for new production processes)