The 4K comment was likely in refrence to streaming providers like Netflix, etc. which don't offer 4K content playback on devives which are not deemed to be adequately locked down, which is a typically a stipulation of their content licensing agreements.
>Or are we stuck using dumb tvs and connecting out laptops to them via HDMI? (And thus no 4K iirc)
HDMI 2.0 (2013) supports 4k/60Hz.
HDMI 2.1 is significantly more ambitious with 8/10k resolution and variable refresh rate.