I think digital store only titles really muddy the waters in terms of completionist collecting. I don't see any reason why people interested in collecting wouldn't also collect PS4/Xbox/Switch games though. To me the more pressing question is, what will happen to retro collecting when consoles stop having physical releases? Kids growing up in that time period won't get the joy of returning to childhood favorites by getting a working console and physical games. That makes me sad, I my self have had a blast putting together a collection of my favorite Genesis and PS1 games along with a lot of consoles from that era.