I've seen many times when a company spend a large sum on canned courses and there is almost no usage. A statistic one of our customers gave us was it cost them $150 per module completed. Each course they purchased consisted of many modules, meaning that they got very poor return on investment.
I believe the problem is that many canned courses purchased as a block of courses are not pertinent to the employees. As an analogy, how many purchased PowerPoint presentations are you using? Why not? My answer would be that the benefit of PowerPoint based training is that you deliver content that is specific to your organization or outlook. Canned content cannot necessarily do that. This also applies to web based content.
If management continues to view employees as (using the Air Force term) "Line Replaceable Units" or "LRUs", they will get what they pay for.
Regarding "extracurricular" activities, it is an interesting irony that people are so interested in using video and podcasts for training but yet want to block youtube and iTunes using the corporate firewall. If the content is interesting, or the employee feels some gain from doing it, they will take the courses (or watch the videos). If management and trainers have to push it on the workers, the knowledge retention will be much lower. Likewise, any impediment to taking the training (e.g. having to go through 3 login screens, having trouble getting the plug-in to work, annoying coworkers with audio) further reduces the chances of course usage.
By making the courses available at off-hours, but simultaneously offering the employee more flexible schedules, you can raise total productivity. If we treat employees as LRU's (or another term I like: "chimp-erators") the employees will remain that way. I have experienced that in most companies there is a breakdown as follows:
20% of the workers are high achievers who do 80% of the work.
60% of the workers treat it as a "job" - they keep their head down hoping they won't be noticed or fired. This group accomplishes 20% of the work.
20% of the employees are either completely useless or spend all their time playing politics to move up the corporate ladder.
eLearning will be most effective on the top 20% since they are self-motivated, and they pull most of the load. I don't have the answer for the other 80%.