It kind of already is killing LX sales, even without the hybrid system, lol.
I agree - the GX has always, since day one, been the disadvantaged little brother. Lexus tuned the GX470 to produce less power than the LX470, despite having the exact same engine. The GX460 also was, predictably, slower than the LX570. "Conveniently", the GX550 accelerates 0-62 basically exactly as fast as the LX600, despite weighing 2-300 pounds less.
You see this type of thing in a lot of places. The Cayman - until very recently - always got the slower, shittier version of the 911 engines, the M2 weighs more than the M4 in some cases, despite being considerably smaller. Manufacturers like to protect their halo models.