That’s so convenient for the wealthy to just buy their way out
And this is the issue with the PGP program overall: it is an economic loser for Canada overall. Therefore, there is essentially no universe in which a government (any government, I mean no party) will agree to have this wide open with no caps (or if no caps, it works the same just you wait however many years as it takes, which - as before here - could stretch close to a decade).
The only solution to make it acceptable for Canada economically with no caps is to charge money - large amounts.
Which, in Canada, will get crucified on exactly the grounds you bring up - just another gift to the wealthy. It will never fly, politically.
That's why I am absolutely NOT kidding when I say a crappy lottery with a small cap backed by the supervisa program (basically a self-funded quasi-permanent residence that primarily benefits the semi-wealthy) is a perfect compromise.
Everyone is unhappy but it's only a modest economic hit, it leaves a little bit of hope, it provides a reasonably practical way for semi-well off parents to spend as much time as they want - and it doesn't touch Canada's political third rail by directly confronting the equality/"Benefits the Rich!" issue.