In answer to your query---
yep--lots of companies require you,the consumer to initiate ( and absorb the inconvenience of) the correcting of their mistakes( this applies to defective goods as well as incomplete shipments or wrong items sent). Deal w/ computer software and hardware companies (even small boutique operations) and experience the joy. Among others. Many people and by extension, the firms they work for, will not accept personal responsibility and will always pass the (depreciated) buck to the perceived weaker entity-- usually the consumer. It's endemic and probably is a sign of tottering empires and societies. End of soapbox.
REI is an exception unto itself so far as large outdoor gear companies go. GG, ULA, and other cottage firms deal w/ their customers like family, as we know. But,for whatever reasons,many companies can't or won't offer the same degree of customer service.
It's the consumer's call whether or not to continue to deal with them.
I'm glad PLG came through for you so completely to rectify their oversight. I would like to ( and will) continue to do business w/ them, too.