A lot of (educated) guesses here. I think the question 'will there be a second-hand market for games' is a good one. I myself could see me buying one game and buying second hand playfields later, but indeed it will take some time for people to have games in their homes, so it'll take some time for the second hand kit market to come into existence and grow 'big enough'. On the other hand, you probably don't want your first playfield to sell in the first few months, and indeed I think more will buy Alien than Full Throttle.
I think one of the major advantages of the Heighway system is not that kits are cheaper, but that 'maintenance-costs' can become less: easy to change parts that you can repair at home (ie flippers, bumpers), changing games between locations without having to move whole cabinets, maybe less trouble because there're no old-school-switches (easier cleaning, no ball hangups if a switch gets 'stuck'). And maybe it'll get the time the game is operating up (les 'down-time').
We'll see if it really works that way (I do hope so for Heighway and operators as well, and for the hobby), but at least I think the effort is worth a 'thumbs up'!
Well, exciting times anyway with Big Lebowski/DP coming, as well as P3 and Time Shock, and Spooky delivering games and Heighway starting to deliver games as well and JJP having produced one game and soon the next one. Stern moving bigger. And I'm sure I'm forgetting some right now . (i.e. Thunderbirds/Homepin. Other startups? And a lot of small projects!)