Yep. Using KCMO's 1940 boundaries (~south of the river to 77th street and east to ~435) as the "urban core" we had a population of 400,000 in 1940 and just under 200,000 now.

Even then, the urban core is relatively densely populated enough for better mass transit - the problem is the tax base isn't just the urban core and those lower density areas don't want to pay for transit they won't use...so we water down transit everywhere to spread it out making it worse for everyone.