It's gotta end eventually, but we're probably a ways off. Even the most successful movie tie-in lines don't last as long as one packaging line look does for Star Wars. Seriously, aside from tiny little sad lines of 2 figure a year from NECA or another company, nothing is as huge as this line, nor will anything ever come close to this level of success for quite some time. If ever, given the toy business today.
If history is any indication, the line is going to end as a surprise-- the last series will be hard to get, and future series will just not get made. The original TMNT line had a year or two of showings at Toy Fair where a chunk of product never got made before going away, and when it went, it was pretty quick. Playmates' original Star Trek range ended with increasingly goofy limited editions and exclusives, with the final batches being Target exclusive figures probably culled from the main line. Or Indiana Jones... just kinda up and ended there, but the writing was clearly on the wall. Which, for Star Wars, it is not. Show me another line with this much new stuff every year that isn't the same body with a new head on it (excepting, of course, the clones.)
Comic Packs have already been pared way back-- the Dark Empire Luke/Palpatine and Republic Quinlan/Faie set were very late 2008 entries. In 2009, we have been given exactly 6 non-exclusive packs, 3 of which just hit about a month ago. It's already on the way out the door, but it's interesting to note that Wal-Mart has had 3 already this year and 3 more are due any time now. On the whole, anything but basic figures tends to come and go in fairly short order, the fact that we got about 3+ years of comic packs is pretty gosh darned great and certainly bolstered the expanded universe toy lineup.
There's still plenty of money to squeeze out of us, so it's not going away. Fans may remember 2004 as a particularly slow year for new basic figures, between Saga and non-Vintage OTC, only 28 new figures were made, plus a couple of POTF2 repaints. By comparison 2003 had 45 basic numbered figures (the last 2002 figures hit early 2003), and 2002 had 54 if you count the Rebel Trooper variant. Things come and go, go up and down. Don't forget, Wal-Mart virtually dropped the entire line save for basic and deluxe figures around the end of 2003 during the Clone Wars push, it was really tough to find some of these items for a while. Things have been absolutely nuts since 2005, and frankly, I'm just fine with a year that doesn't have $600+ worth of exclusives in Q4 before the basic line even comes into consideration.
40-45 "new/refresh" (assuming "refresh" is slang for "new accessories/slight retools/repaints") is totally reasonable to me. We got 44 in 2008. We got 35 so far in 2009, with another 22 or so likely before the end of the year. I'm sure there will always be a couple of token Cantina aliens and Jabba's Palace aliens each year, just to keep us interested, alongside the token Han/Luke/Anakin refreshes. If Hasbro and Toys "R" Us can successfully sell a $50 TIE Interceptor this holiday season, seriously, what do we have to worry about?
When Wal-Mart drops the basic movie-themed figure line (which probably won't be "Legacy" or "Build-a-droid" forever anyway), that's when I'll expect the line to die in 6-12 months.