Every package is used in every part of the industry. Some packages are used more in certian industrys, such as LW=TV Maya=Movies Max=Games. Now that dosent apply to each package as a total rule of thumb. For instance LW has been used in many many many movies just not as much as maya. LW has also been used to design games but probbly not as much as max.
Check out this LW list--->
http://adh.best.vwh.net/lwproj.html
If you are shooting for movies as your 3D medium where you want to do lots of work then you will probbly have to learn Maya at some point.
LightWave is becomeing more popular for movies now (Than it has been in the past) because industry 3D artists and producers are realizing its power and it offers a great cost advantage over maya.
If your going for a 3D job as a modeler then LightWave is widely recognized as the most robust 3D modeler out there. Some projects like Final Fantasy (movie) use Lightwave to model in and Maya to animate.
The 3D concepts you learn in lightwave can easly be applyed to other packages like Maya.
No you havent wasted the last six months. LW is used in many many many modeling projects and movies. I would stick with LW learn about 3D and dabble in the other packages.