Tesla cannot currently match demand for its vehicles, and as such must increase prices of vehicles being sold to match the expected price when that vehicle will eventually be built.
If you are building vehicles immediately on request, then you can offer prices closer to what you are currently paying for materials, but the further the build moves into the future, the more expensive those are likely to be.
That being said, Tesla can also just raise its prices due to strong demand and nothing else. It is under no obligation to reduce its prices, just because it can afford to.
That additional profit, will serve Tesla better moving forwards with its continued expansion.

I just wish this led to the lowering of the price of the vehicle itself, as the battery is the main point of the cost overall.

The article doesn't touch other primary advantages of LFP/LiFePO4 batteries. They are much less prone to runaway heat conditions that can cause fire so they are much safter,  and they typically have far greater cycle life (the number of discharge/recharge cycles they can go through without degrading).   So these new 'cheaper' battery packs should be safer and last longer than the nickel / cobalt previously used. 

I've been running my house off solar with 15.5kwh of LFP batteries for years now.  Great stuff!