Sometimes the older kitchen's wood looks darker just because of aging. Ie the finish often was not that dark when new at all. Folks clean with ammonia, the finish darkens due to fumes and dirt.
From a makeover kitchen designer, the old set up is always obsolete.
There is quite a high profit in makeovers.
The retired couple hears their ranch style house is obsolete, the new oven now has them bending over more! folks fork over 50K in a makeover, and now have to bend over to use the oven. Often it really does not matter, they are just remodeling for show!
Most folks want new stuff, thus old real wood cabinets are replaced with particle board. I have seen where a "1960's kitchen WORK triangle" is now lost and replaced since the designer has better ideas, hidden refrigerators.
A neighbor is gutting an early 1970's house's kitchen. Thus that great nice 3 hole premium sink has to go! It its place is a made in China 2 hole sink that is smaller. The original had a view looking across the water, the modern upgrade has one looking at a blank wall.
Some remodels are better, others may not be functionally.
Many of these Kitchens cabinets were not that dark when brand new, the wood got darker. Folks stained them darker too.
Our fully custom kitchen in a custom house we built in 1952 had pure wood cabinets that were really light pecan. When we moved away the new owners painted them white. Yet another new owner painted them real dark ; scuttlebut we got via Xmas cards from neighbors.