Those were the days- solid walnut! Even by the 1950s cost and availability had limited Brunswick to veneered Walnut on the Anniversary table. Imagine a solid Walnut piece of furniture this size today- if even possible.
Certainly it is possible.
Walnut is not even a particularly high priced lumber - though it is a lot more expensive than poplar. One problem is that the best walnut logs do go for veneer. Another factor is that it is common at the mill to steam walnut, which makes it kind of muddy looking and makes all the white sapwood dark gray. With stain on top, it all looks like uniform dark heartwood. For some work such as entry doors & jambs, the steamed sapwood will both fade after moderate direct exposure to sunlight, and it is not rot resistant, like walnut heartwood is.
So the furniture or millwork builder might have to buy more volume to build the same piece compared with say, cherry or oak etc. especially if specifying/buying "unsteamed".
For instance, to make a typical entry door, i figure on buying at least twice as much or more walnut for the same size door, compared to Oak.
In order to sort pieces to exclude sapwood, and for straight grain/ stability.
Regarding walnut, or even oak, a vertical laminated core for stiles and rails with thick veneer over (as has been done for a couple centuries in some of the best work) would arguably be a better product for the customer combined with 3-ply panels; but the lumber is not yet quite expensive enough that it would make sense for me given the significant increase in labor.
The reason Brunswick's tables going back to the 19th c were primarily veneered is stability.
Though i am sure all the rosewood faced/veneered rails on so many of their better tables before the 1960's and before formica became preferred, were for cost reasons, mostly. That wood in larger pieces has been really expensive for a very long time - back before civil war days when it was popular for bent laminated furniture that was then carved all over (Belter furniture, e.g.).
smt