The Canadian funds like VEQT/XBAL/etc are overly concentrated in Canada on purpose because it reduces volatility:

* https://www.vanguard.ca/content/dam/intl/americas/canada/en/...

* https://benderbenderbortolotti.com/home-bias-in-the-vanguard...

Vanguard/Blackrock could set the allocation to whatever they wanted, but it's a conscious choice. Absolute returns are not necessarily the only consideration (if they are, perhaps buy a NASDAQ fund).