Geek note, QQQ isn't cap weighted. It has its own unique weighting formula, and the difference is material.

I think QQQ weighting matches NDX weighting within fairly tight limits which are set out in the prospectus.

The weighting in the index is modified to reduce the weighting of a stock if it exceeds a certain limit, or a group of stocks weighting can be reduced if their aggregate weighting exceeds a certain amount.

The adjustments push (slightly)QQQ towards QQQE weighting

connect.rightprospectus.com: Hosted Site

Rebalancing of the Index
The Index is calculated using a “modified market capitalization-weighted”
methodology, which is a hybrid between equal weighting and conventional
capitalization weighting. This methodology is expected to: (1) retain in general the
economic attributes of capitalization weighting; (2) promote portfolio weight
diversification (thereby limiting domination of the Index by a few large stocks);
(3) reduce Index performance distortion by preserving the capitalization ranking of
companies; and (4) reduce market impact on the smallest Index Securities from
necessary weight rebalancings.

Aussi