I can buy the Predators new, OTD pricing is $389. The standard rifles locally are $350 OTD. Most any of the online sellers will ship one to your FFL for around $400. I have three Predators, 6.5 CM, 308, and 223.
Ruger didn't pioneer any of the cost savings steps, but did a good job of incorporating them all together in one rifle. Many of the cost cutting steps are also responsible for the improved accuracy.
The closed top receiver is easier to manufacture, and makes the action stiffer.
And since the closed top requires a DBM that step also reduces costs and helps make the rifle more accurate. Getting an internal magazine to fit and work properly is just one more step to complicate accuracy. It can work, but adds to manufacturing costs.
Savage deserves credit for developing a completely different way of bedding the action to the stock that means much less precise machining, yet makes a more accurate rifle. Ruger borrowed heavily from Savage with their V-Block bedding system. This means that an expensive stiff stock simply isn't necessary for accuracy. They can save a lot of money on the stock and still get great accuracy.
Ruger also borrowed the Accutrigger from Savage. Normally a trigger that can be adjusted so light would be considered too dangerous for a production rifle. The addition of the blade inside the trigger makes it all but impossible for the gun to fire if dropped even with the trigger as light as is possible with them.
The 3 lug bolt with a much larger diameter bolt body also contributes to accuracy while being easier to manufacture.
If you look closely you'll see most of these same features on several budget guns, and they all shoot better than the price tag says they should. The Tikka T3 was one of the 1st. But the Savage Axis, Browning X bolt, Winchester XPR, TC Venture, and probably a couple more I've forgotten all incorporate most of these features. It's simply a new way of thinking about what works. And its hard to argue that it works.
When the Rugers 1st came out I didn't have confidence that they would be reliable enough for a dependable hunting rifle. I thought of them as range guns, or back door hunting rifles. Not something I'd take on an out of state big game hunt. The original magazines were the weak link IMO. But the most recent guns are shipping with better, newly redesigned magazine. I don't have any reservations about using one of them anywhere now.
And while I have acquired some "nice" rifles over the years, some with $1000+ invested, none can match the Ruger Predators for accuracy. Especially the 6.5 and 223.