Dude, just explain the fact that you need HDMI switching on your receiver in order to run a blu ray into it. Explain the differential cost of the new one and what you will get for selling your current one.
Honestly I would prep it and wait 2 more months until the pre xmas sales start to happen.
I personally have done enough spending on home improvements, family holidays and diamond earrings, leather coat for my wife that when a couple speakers roll in she doesnt care.
Then again, my wife likes the HT gear, she just doesnt care to know the technology behind it. If she can watch "The Sound of Music" or any other current releases in 5.1 on the 61" set ....its all good.