people have been saying that for years.
That's true and we're not there yet, but lately there are starting to be practical alternatives.
When a 32-bit chip is the same size and cost as the 8-bit chip and you don't need 5v (increasingly the case) or high current drive on all pins then why use an 8-bitter? Except for the "high current" part all the other things are currently the case, in fact LPCs are always cheaper than a similar AVR, sometimes by a lot.
I'm about to get a board made, it's a dual processor with an LPC1227 and an ATmega1284. These chips are very similar if you look at serial ports, pins, memory etc. But the LPC is half the price, twice the clock speed, probably 3-4x the execution speed, flat address space, no frigging with PROGMEM, FIFOs on the SPI and UARTs etc etc.
So why use the 1284 at all? Basically I want the board to be Arduino compatible and I reckon the 1284 has the best mix of features of all the AVR chips.
Rob