To be frank, this compensation issue isn't a problem specific to Amazon. It's common knowledge that if you want significant raises (50%+) you have to jump among the FAANGs/Tier1 companies, mainly due to the external vs internal offer policies. An internal promo will get you into the bottom of the next pay band versus an external offer which usually puts you near the top. The compensation delta can be in the 6 figures for non-new grad roles. This holds true all the way up to director level roles in my observations.

Fair or not, this is currently the optimal career/comp progression strategy, although recent hiring downturns might change the meta(heh)game to favor internal candidates. We shall see.