I remember when Ramline introduced the first 10/22 banana clips with plastic feed lips. They worked till the plastic began to wear away then it was jam-o-matic junk.
Next came Butler Creek with a better quality red plastic feed lip.....big improvement.
Mitchell offered a 50 round tear drop drum with metal lips that were great, but not cheap. Along came the Clinton AWB and they disappeared from the marketplace.
Then everyone discovered that the metal feed lips were the most reliable and almost everyone offers them.
Why it took Ruger so long to catch on is a mystery, but they make the nicest ones out there now.