That's not true. Apple drops the price on older models while continuing to sell them alongside the newest ones. The cheapest new iPhone you can buy is $450.
Yea so you can buy old models at a cheaper price. 2 years from now maybe you'll be able to buy the Apple Watch 1 for $250 or something but most people will want the latest version. I seriously doubt we'd ever see Apple sell the Watch for $100, that's just not how they do business.