One problem may be that building specific units of product functionality is considered junior-level work. Doing so quickly and with high quality can get you a n

One problem may be that building specific units of product functionality is considered junior-level work. Doing so quickly and with high quality can get you a nice $20,000 bonus, but not the $200,000 RSU bump associated with promotion to the next level. A higher level engineer is meant to "scale her impact" by owning the architecture, the platform, the playground in which other engineers live. In backend world there are opportunities to do this in nearly any business domain or sufficiently complex problem. But a company only needs so many UI frameworks. As such we see very good, long tenured mobile and frontend engineers simply cranking out feature after feature. There's no career progression that way.