Compared to post 1960 Post War, look at the very late engines, no e-unit, no head light, no working couplers, and some looked like blocks of plastic engines the detail was so low, MPC after 1972 had it beat with ease. What at the part lists of these MPC DC sets? I hear of them but never see them. I have a pair of U36B that received no maintenance for forty years and they still run great. MPc had a bad reputation, that for all i know is a carry over from the late post war that was really cheap in both detail and functionality. All the MPC i have is great, bit stiff from age, but runs great.
#8350, 8670, 8769, 8903, 8001, 8007, 8212, 8314, 8515, 8625, 8803, 8903, 8905, 18700, 18704-18707, and some 8005 Generals, are dc only. (Some of those are 1990s. One JC Penney version is die cast that I know of(forget the number, might be listed here? Mine has been converted to post war power.
Your U boat isn't an off the shelf starter set. My chrome General is a great deal different too. If you offered me a new MPC or an old pw loco back then, I still would have reached for the oldest pw on the table. The "cheapening" began in the mid 50s with the type 2 motor. It was downhill for a decade too. I.e. I'm not a big upright T2 fan. All Gramps Type1s spoiled me! Ive had good luck with single fields, but the later dual fields die on me (6?) I've only hat 2 in frame steamers die in 50+ years; 1 pw/1 mpc... Oh, and ran a couple plastic motor framed Scouts till they croaked. Talk about cheap pw, the "Scout motor" needs mention too, many saw the trash early on.
I dont think you see them (dc starters) as often because many ended up in the garbage as well, toasted by an old ac transformer. I am aware and iIhave still toasted 3 by accident (a cheap mistake though, new has been $3-$11.) The sad thing is "penny" diodes were all that was really needed from Lionel. The Kickapoo ticked me off first though I think. An ac set of the day, had very cheap bobber cars; I recall thinking they looked more like Fisher/Price vs Lionel (I sort of like the cars now, I'm not as picky as when I was young, lol) The standard mpc starter’s semi scale boxcars got plastic snap in frames and plastic wheels (great graphics and color, but in need of weight and metal wheel swap to be worth a crap. Most compairable size Fisher Price items weigh more . ).
The warning on the dc packaging was small, unnoticeable, weakly expressed, and unexpected by generations of Lionel ac users, especially the casual/holiday folks. The avid hobbiests were mostly aware. IMO, Sears and Kmart stopped selling sets in store due to MPC "quality" and a reluctance by them to accept returns of items from the stores. Tyco took away the kmart shelf space and bench display area, Atari took the big isle away at Sears, Tyco unaffected, etc etc (the top selling Sears in the USA too). And you know Detroit was pretty loyal to local businesses )