Perhaps it is, but a zoo without animals is not a zoo.
Your memories of the National zoo differ from mine. I was a kid who went a couple of times a year. They had animals of every kind ,some of which amazed me as a kid. Herds of Zebra, Wildebeests,they had Prairie dogs, Panthers and white Tigers.
Perhaps you are right , Kids can see these animals on a video tape now, they dont need to see the real thing. I guess the animals they do have left over there will just be allowed to go as they die off. Probably all for the best.I do know I wont be going there again , but if you like to hike and climb a large hill and be ripped off by high price concessions, give it a shot. There are a couple of elephants left, and an old mangy male lion. LOL
There are a few more animals left there, but not enough to make it worthwhile paying the 20 buck parking fee and traipsing that hill with two Grandkids in tow.