Even if you wait until in your seat to pull up the paperwork, 30 minutes is plenty of time. Downloading and reviewing takes 5 minutes at the max. Unless you’re new, most of us can do everything else by ourselves in 15 minutes, with 2 people working together splitting the load it goes even faster. If the meet and brief did in fact enhance safety there would be measurable data showing that United had a better record than AA, NWA, DAL, CAL, ...... There’s not because no major US airline is the gold standard as to what a professional pilot should be. The only difference is the color of your uniform and w2.