Back to the topic of 4k restorations, another factor will be if the UHD format survives or catches on.

There are signs that the whole US home entertainment industry is in decline:

http://www.nscreenmedia.com/us-home-entertainment-spending-q4-2016/

One of the key points was :

2016 saw big growth in the number of 4K televisions in consumer homes, and the introduction of the 4K Blu-ray disc. DEG says there were 10 million 4K UHD TVs sold in the US last year. As well, 300,000 4K UHD Blu-ray players were sold. By the end of 2016, there were 110 UHD Blu-ray titles available, with another 250 promised by the end of this year.

Despite all this positive news, disc sales and rentals continued to plummet. Disc sales were down 9.6% on the year (to $5.5B), a slightly better performance than the 12.5% decline in 2015. However, physical rentals were dramatically lower, with store rentals down 21% and kiosk transactions down 17%. Last year they both fell 11% and 9.5% respectively. The entire physical disc rental market spend was $2.5B, down from $5B in 2011.