Why not go even further and make the right axis go up to 100,000? Then you wouldn't really even be able to see any decline at all!

</sarcasm>

But seriously, no, the chart doesn't have to go down to $0 in order to be useful. All you're doing is compressing the data. The original chart makes it very obvious that the manufacturing employment has gone significantly lower than it was back in 1947. Your new chart obscures that, makes it so if I just glance at it, I might come away with the impression that it's close to where it was in 1947, when in fact it's something like 20% lower.

That said, I wouldn't complain if you simply wanted to extend the chart a little downwards, maybe down to $8k or $9k, rather than dropping it to $0.