One of the ways which can be used to lower individual costs is to pool groups of people to help pay for a single test. Oftentimes women (who have no YDNA to test) would be interested in learning more about the Y-DNA of their father, etc. and cousins can get together to test a single individual.
I have been into genealogy for almost 10 years and DNA for over 5 and I have been involved in some "pooling endeavours" but they are the exception rather than the rule. There are so many people out there who we would all like to be tested (whether they come from an area of particular interest, have the same surname, or whatever) and can't afford to test themselves, that pooling will not even scratch the surface of all these as yet untested people. Most people watch Whodoyouthinkthatyouare or whatever, have a quick stab at genealogy and then give up when it gets too hard/expensive, but just because they stop doesn't mean they wouldn't get their DNA tested if they could afford it.
However, I'm not sure if YDNA STR testing will go much lower.
I'm sorry, I probably chose the wrong board to post this on, as I was thinking mainly of surname DNA Projects. If prices for STR testing do not go any lower I think we may soon see surname projects grinding to a halt. The ones I am already involved in seem to already be slowing; when new results are announced these days they seem mostly to be already existing members upgrading their results, rather than completely new members joining. And when they are new members, they are often fairly close relatives of existing members, rather than people from unrepresented families.
With regards to SNP testing, it seems to me that we will soon get to the stage that newly discovered SNPs don't really yield any meaningful information, other than being in sub-group XK$-5 rather than XK$-6 of group XK$. Just a different bunch of surnames, and no more.
Reducing the cost of STR testing, as well as SNP testing, is vital for the long term health of the DNA community imo.