Also I think the issue is not that bad as it affects mainly desktop version (mobile mostly have content stacked) of sites and people on those are "usually" on faster connections.
The sub-pages on this site are relatively bouncy to me during the first load.
Example:
https://www.intercom.com/customers
Environment: Relatively fast PC (4 cores @ 4.0 GHz, 24 GB RAM, SSD, etc) running Chrome. Large screen (40", 4k running in 150% scale with the browser maximized in size). 250/100 Mbit/s connection. Located in northern Europe.
Also tried throttling the connection and I don't see anything annoying in how the page layout happens.