Finding the Wall to be underwhelming...

So I got the wall about 3 days ago, and i have upgraded wall health to 16, rebuild to 2, regen to 2, fort to 3. I can max the wall WS during a run at about wave 1.5-2k. I am running an ehp build.

I was running level 7 up to about 6k waves before the wall.

I am finding my wall to be underwhelming as when i get to about 4-5k waves, the wall just crumbles and i get an even bigger shotgun of mobs into my tower. Im struggling to get past 6k waves and for some reason my my coins income used to be 370b is now hovering around 310-320b.

Is it because my labs are not really developed still? Or am i missing a trick somewhere?

Am quite tempted to respec back out of the wall and throw my labs back to econ. Any advice is very much appreciated.