I suppose the pertinent word is "maintain".
Is if frowned upon to temporarily open up more than 2 connections to aid speedy loading of complex pages (e.g. ones with dozens of images) provided those connections are closed once all elements are downloaded?
If 'keep alive' does, indeed, "keep alive" all opened connections (e.g. if you set 10 connections per server, so the web page completes faster, and 'keep alive' holds open the final 10 connections) then "we" have a problem - particularly Chrome, as the "max connections" is fixed at 6 (unless Chrome has a separate limit on keep alive connections).
The ambiguity is where RFC:2616 says "SHOULD limit the number of simultaneous connections that they maintain to a given server" but doesn't really define "maintain".
Is a maintained connection defined as one which is held open (e.g. if there are 10 max connections set up and there are 10 live streaming thumbnail videos, then presumably all ten are held open).
Is a connection held open only long enough for an image to be transferred (before closing and moving on to grab another element) not categorized as a "maintained" connection?
I'm going to quote figures from Firefox (only because they're easier to obtain than trawling through the registry to find the same figures for IE)...
network.http.max-connections default integer 256
network.http.max-persistent-connections-per-proxy default integer 8
network.http.max-persistent-connections-per-server default integer 6
So clearly FF default settings go against the limits defined in RFC:2616 (unless these are not counted towards the "maintained connections" - although the word "persistent" could be taken to mean "maintain").
In fact it seems only IE8 (and below) has a limit of 2 (and that's only for http1.0 - for http1.1 the IE default is 6, so that also goes against RFC:2616).
I find it hard to imagine MS, Google and Mozilla would collectively (and presumably; independently) decide to breach RFC:2616 unless the maintained (keep alive) connections are limited, elsewhere, to 2 - or unless those limits in RFC:2616 no longer apply (possibly because it was written 13 years ago, at a time when most office local LAN connections were slower than it's possible for home internet connections to go these days???).
vDSL2 FTTC Infinity with BT
DL Sync 80Mbps
UL Sync 20Mbps