I watch memory use numbers and i see this:
panel 71 Mbs, runner 51 Mbs, notificationsd 49 Mbs, kactivitymanagerd 48 Mb, powermanagement 48Mb, kdeinit4 46 Mb, session 44 Mb, policykit 44 Mb, openbox 35 Mb, etc,
And I remember my first HDD was only 40 Mbs and it did run MS WOS 3.1 for workgroups before being retired.
There must be a way of replacing them from RAM and put a small package that would CALL or WAKE UP the big package from the HDD as old TSR programs did. I do not think all is always necessary at RAM , there must be a way of divide and conquer or to split them into always at RAM part and ready for CALL part or even only a small program in order only to call that program and also do not loose a lot of speed.
There is still p4 laptops that had only 128 Mbs of RAM - my sister has one - and they must be able to run the lighter DE.
LXQT and KDE at Qt side and XFCE and GNOME at GTK will be the 4 big DEs one light and the other not so light, and Pantheon, Cinnamon Mate Unity and others will have also their role.
Being the smaller in RAM use, even it is cheap now, will give LXQT the crown at old hardware and even at hard linux gamers to come - because they like it light -