Eh, I don't think anyone is flipping out. The prices have been jumping up, that's just how it is. Complaining about it is pointless, but speculating about increases for years as they happen isn't.
When I first started collecting, a regular MMS figure like Bank Robber Joker and T-1000 (both of which had multiple heads and a buttload of accessories), cost $140-$150 each (which I thought was high for a doll, even then). Now, a crappy barebones MMS figure like ASM2 Spider-Man or TDW Loki is $230. $230! That big Robocop w/ Jetpack was $150, now a Robocop with diecast is $300 (or $430 with a plastic chair). My first DX figure was DX 01 Joker. It too was a pretty impressive release in terms of "stuff" and the MSRP was $170 (DX 02 too). What's the average price for a DX figure now? $264 to $300 (DX 08 - DX 13). That's about a $100 jump in just the last couple of years.
Like wise the vehicles and bigger characters shot up. Back in 2006, ED was about $200. Today? An ED (with awful electronics) cost $400. The Tumbler was $400 right out the gate back when it first debuted for TDK, then the '89 Batmobile showed up at a whopping $630. We're not talking small increments here and there, we're talking massive jumps. Now we have a 1/12 vehicle that's a little smaller than the '89 Batmobile (their largest item to date), and that sucker is pushing $800. True, it comes with two small action figures, but I doubt two characters and a plastic orb equate to $200. They don't seem any more detailed than Hasbro's Star Wars Black Series figures, and those are $20 a pop. Their upcoming Jabba and Speeder Bike deluxe figures are $40.
Saying their next big ticket item will be $1,000, an MMS $300, and a DX $350 isn't a stretch, it'll happen. With each release they push the threshold, while collectors complain and buy anyway.