It would just be nice if they were configurable, understandable and actually worked for me. Some systems’ “We’re showing you this because ...” is an important first step, but it needs to go way, way, further.
Big companies probably don’t do it because they’re afraid of overwhelming a user, disclosing too much about their own algorithm and the things they know (“We’re showing you this because someone you hung out with on Instagram just before you met”).
Thus it’s probably up to open source projects again to make algorithms that actually work for people, not against them.
Are there any such projects already? Are there projects trying to dissect common proprietary recommendation systems? They’re some of the most mysterious influences on current society.