Many of the important decisions are made at design and review time. When that team adds PDF support, they should act unlike the Explorer team and avoid unnecessary O(n^2) algorithms.

Part of getting this to happen is setting the right culture and incentives. PM is such a nebulous term that I can't say this definitively, but I don't think the responsibility for this lies with them. Some poor performance is simply tech debt and should be tackled in the same way.

$WORD_PROCESSOR employees should be capable of this: we've all seen how they interview.