So people who are good at managing money, who tend to avoid credit, don't get a chance to demonstrate good -credit- management and hence end up with a low score.
This is one reason why getting a credit card, using it, and then paying it off in full every month is a valuable thing to do.
So for all the good money managers out there, be even smarter - build a good credit management history as a side effect of your good money management. That'll pay off in the long run.
All your savings will evaporate when you can’t get a good mortgage rate. That’s not good money management
Re: mortgages. IDK how things are where you're at, but from what I've seen, with houses of equal valuation, the value of the monthly with a mortgage will typically be more than double than when renting. Renting, saving, then buying out of one's pocket (likely a lower valuation house than when renting) seems like a viable strategy. Mortagages aren't some unavoidable fact of life.
It may or may not be what gives the best result, but that's ok. The peace of mind of not being in debt and having greater savings may be worth it, and have second order effects like enabling you to take more risk in other parts of your life.