To me, deep and broad aren't mutual exclusive. My take is that well read persons are, to use the technobabble du jour, "tee-shaped".

Or rather double/triple/quadrouple/n-ple tee-shaped having read broadly across many fields and comparatively deeply in more than one. Relative depth in multiple areas becomes easier and more likely with age as interests change and realized opportunities to read to greater depth accumulate.

Reading deeply requires time. Reading broadly requires time. Neither has a shortcut. Neither precludes the other given a lifetime.