The Property Stock & Business Agents legislation provides that any strata management agreement must disclose any commissions the strata manager may be paid.
If it doesn’t, the strata manager has to pay back the commission.
Financial institutions don’t pay bonuses/commissions to anyone for placing money with them – they don’t need to.
I am sure there are strata managers taking kick-backs just as there are in any industry, I knew one who did, but it is not that common, and applies to any sphere.