K shaped economy with increasing expenditure means the wealthier increase their spending as a portion of the economy and at an absolute level. It is not interpreted as the polity doing well - if anything, it is cause for concern.
Inequality is very visible in terms of what sort of consumption occurs. Gotta look at the qualitatives.
The retired middle class boomers I know are completely outside the business cycle.
While I don't think they have enough to really be considered wealthy, they have no mortgage payment, a social security check, a pension and most have a 401k.
The business cycle will not change their spending one bit.
Being an aging human is a suicide note. The extra steps are the entire point of retirement.