Yes, physical security measures are not a guarantee. As noted, they are primarily intended to buy you the time to take appropriate action inside the house. However, they also have the benefit of being a deterrent. If you take reasonable measures to harden your home and, in the process, all the other homes around you become easier targets, that's a good thing and can reduce your chances of being targeted.
The danger of "accepting" that all physical security measures can be breached with enough force or skill is that it encourages people not to do anything to improve their security. If you adopt the mindset that "no matter what I do, they'll get in anyway," you're already on the road to failure.
Stack the odds in your favor in as many ways as you can.
Stay safe,
Mike