There are so many different facets to this issue. Part of the issue is that there seldom is a true "technical ladder" for advancement aside from the managerial ladder. And the people who are on the managerial ladder can't understand why someone would "be content" to stay in the same position for years. If you are not trying to advance on the managerial ladder (and get paid more money), there must be something wrong with you.

Way back in 1999, the first-level supervisor position for the group I was in was "deleted" from the organizational chart during a merger with a firm in another city. After a few months, it was apparent that having a long-distance supervisor didn't make sense. I stepped up to the plate to do that role - no change in title, no pay increase! The following year, the company began an initiative to convert our mainframe, flatfile databases to a relational database. I was pumped! I had a lot of ideas and wanted to be on that development team. So I requested a transfer into that group, and stepped down from my "supervisor" role. I was floored by the disdain that people on the managerial ladder had for me after I stepped down - sort of, "See, we knew you didn't have the chops to be a manager." (Not only that, but the development team spent all their time in meetings, never agreeing on the direction to go, and no development actually took place. I ended up leaving the company just a few months later, to start fresh and learn again.)

Oh, I meant to close with: I would advocate a true technical ladder, with something like "Head guru" at the top. The people on this track could be involved in multiple projects, lending their years of experience to planning and oversight. The company could even encourage advanced degrees for people on this track.