In the 1970s you were not spending a few million on rejuvenation treatments, a few million on augmentations, a few million on personality back up and clone body replacement insurance, and that's before you start buying proper gear - state of the art drones, robots, computer gear, weapons, armour etc.
Like I said a few million credits just isn't going to go very far in the toy shop.
No, in the 70's you were paying for state of the art cars (seatbelts! AM/FM/8 Track stereo), state of the art home electronics (color console TV with REMOTE! Quadraphonic hi fi system. PONG!, and that $100(!!!) LED watch), long distance phone calls, bell bottoms, leisure suits, available air travel, and state of the art medical care. This was all pretty much routine to the middle class.
Yachts, exotic cars, mansions, private planes, all of the other things associated with Millionaires were, obviously, not associated with the middle class.
if a house mortgage in the 3rd Imperium is running 100,000Cr, like it was in the 1980 dollars, then rejuv's, augmentations, personality backups, clones, drones, robots, and "gear" for millions of credits were not middle class items. They are actually, figuratively, and even spiritually, out of reach. The stuff of fantasy and glossy magazines.
So, given a choice between dropping 1MCr of free cash on, well, any of those vs paying off the family house, putting the kids through school, splurging on a nice [car, boat, computer, bucket list trip] and sticking the rest in the bank for retirement -- that's really a no brainer for a lot of folks, frankly.
Simply, either 1MCr is "a lot of money" or its not. If it's not, it's not. Maybe the CrImp is more like the Lira or the Zimbabwe dollar. But thats not the story I've been hearing.
The fact that some things are expensive, suggests that they are not common. If they are common, then there's a lot of money in the middle class.