Spielberg did not win an Oscar before ‘Schindler’s List’. ‘Empire of the Sun’ is flawed but has held up as a pretty good film - a neat David Lean tribute (he was originally supposed to do it) with Christan Bale’s best performance to date.
Well he got the Irwin Thalberg “consistently good stuff” Oscar in ‘87, plus plenty of nominations before hand, plus a bunch of nominations from BAFTA and the guild and a couple of wins. By 1990 he’d had more nominations than 90% of directors will ever get and he was only 27, sure he hadn’t won “the big one” but he’d gotten enough recognition that I wouldn’t declare anything he did a cynical attempt to get the big one, which was your question. Most of his movies, important or not, hold up as pretty good films. I just get tired of them, especially the important ones.