You do realize that every latency you see on residential connections is magnified on mobile or even satellite connections?
If you have a RTT of seconds, 10 additional roundtrips can cost an entire minute.
These things become very noticeable very quickly if the system is in non-perfect environments.
Additionally, even with modern browsers it takes far too long to open a website — it should be 100% instant, less than one or two frames (16 or 33ms). That's not possible, as RTT is usually around 18ms between users and CDN edges, but at least it should be below perceivable delays (100ms).
EDIT:
My best websites hover around 281ms to start of transfer, and 400ms to the site being finished.
That's improvable, but most sites out there take literally half a minute to load.
Now go on a 64kbps connection, and try again. Handshake takes seconds, start of transfer is almost after 30sec, and by the time your website arrives your coffee has gone cold (a few minutes for a google search).
Years ago, Google was usable on dial-up. Now even the handshake takes as long as an entire search used to take. Notice anything?