just feel that this needs to be shows,
average cheap $50-60 router from 2011 (google router fccid and pick a few and look them up on the FCC website)
here is a dbm to watt chart
http://www.cpcstech.com/dbm-to-watt-conversion-information.htm
you will see that there is no need to spend $170 for 600mw of transmit power
(Also some of the higher end $150-200 routers from companies such as netgear will over over 600mw, generally around 800mw+ of power)
Now lets look at a router from 10 years ago (one of my favorite routers, the WRT54G)
yep if you look at that chart, right around 45mw of transmit power.
They are basically comparing their 2012 router, to routers from nearly 10 years ago just so that they can justify their insane prices.
PS from 2002 to 2012 and probably beyond, most routers that do not use high gain antennas, will use a 2.5 to 3dbi antenna, and the ones with internal antennas will attempt to account for you not being able to position the antennas by using a combination of 2.5 and 1.8db antennas (the higher the gain, the more directional the signal becomes and thus the less hight it can handle.
if you live in a 3+ floor house, a 3dbi antenna will give you better coverage than a 7 dbi antenna (average high gain antenna) but if you are okay with a little bit of modding, you can easily add rp-sma connectors to almost any router with internal antennas, and then use 20db gain antennas if you want. (7-9db antennas are good for single level homes) and for multi level homes it is best not to go over 5db unless you are okay with positioning the antennas in a way where it aims to a specific area in the upper level of the home.