This is pretty much on the money. Car safety with respect to the occupants is increasing over time, but it has always also increased over the budget with the time pegged to a certain point. So your 1997 high end car may well be safer than your 2015 budget car.
Case in point: I've restored a Daihatsu Trevis, a small Japanese budget car, and after working on it and bringing it back up to the standard required to pass a salvage title inspection (which is a higher standard than the original one where I live, you have to book an inspection for the vehicle that takes several hours and that will have cross frame measurements and all kinds of assessments to make sure that the vehicle is safe) I decided that this is not a car that is suitable for many kilometers of highway driving. A crash in that car that would be survivable in even the cheapest Golf or Skoda would be lethal in that little car. So I ended up passing it on to people that only drive in the city and got an elderly Golf instead.
And a Golf was definitely not the high end of safety at that time, but it was tons better than the much more modern Trevis.