I'll agree with you anything can be built, but for the first time lathe buyer, I'd still recommend not buying a lathe that wasn't complete, a new lathe owner has enough of a learning curve the way it is, no need to discourage anyone from the git go with added complications and needing to put together a lathe package from scratch on top of the not exactly knowing what's all needed in the first place.
I stumbled into my first lathe, a county shop was selling it off at auction and I knew the guy who ran it, he was the only one in the shop to know anything about the lathe, let alone how to use it. I talked to the operator ahead of time and he told me, if I was interested in it, and would actually use it, he'd make sure it was complete with all the tooling there was for it. I got everything they had for one price.
Fast forward a couple decades to last year, a local machine shop was selling out, they had four lathes they sold on auction, I also knew the guy who ran them and talked to him ahead of time, he told to not bid on any of them, turns out the flunky auctioneer that was conducting the sale got everything screwed up and only the person who ran the machines knew about it, they mismatched parts, components, change gears, taper attachments and nothing was even close to being partially complete, and nothing matched anything.
Turns out another shop bought one of the newer lathes, but now can't cut any threads, none of the speed change sprockets are even matched for the lathe, the taper attachment isn't complete and nobody knows where the parts are even at or what box of junk any of the speed change gears and metric gears were even in on the sale, the chucks don't match the spindles, didn't get the correct chuck wrenches, the live centers don't match the lathe, nor do any of the rest of the tooling, there were junk chucks sold on the sale but the auctioneer got them mixed up as well, the good new one's sold as junk and the junk one's went with the lathes and the list is endless as to the mistakes made. The new owner of one lathe who's also a young guy who didn't know exactly what he was buying is now facing the reality, he owns a very large paperweight that will cost him far more than its worth to even attempt to find the components that match it so he can even turn it on or chuck anything in it, I'm thinking there will be a lawsuit over it before its done, it was an internet auction and when the public viewed everything, they were all complete, when the auction was over and they went to pick up the items, most never noticed things didn't match or were incomplete till they got them home. The upside is, the new owner now has dozens of spare parts for milling machines, junked out lathes from a half century ago, change gears and metric gears for lathes traded thirty years ago on the one's sold at auction and list is endless.
If your new to lathes, take someone along who's run one, knows something about them and go look and run whatever your wanting to buy, verify things are complete and matched to the lathe your buying, check everything out and change gears and make sure they are matched to the lathe and fit, try all the chucks out and make sure they hold a shaft tight, run the lathe and check for play and accuracy, if you don't know how to do this, fess up and admit it, and get help when looking, there is no shame in not knowing, the shame comes from getting took on a pile of junk, we all learn as we go and continue to learn till we die.
Age of a lathe means little to me, condition and access to all the tooling means far more than age or brand and that depends on where in the world your located as well.
If your not buying a lathe that's complete, make sure beforehand its new enough you can buy what you need to match it, like everyone else in the world, when you need it, you need it now, not doing the scavenger hunt and wait a few years till you find that metric change gear so you can cut that metric thread you need today, cause the part is on backorder for six months and you need the machine tomorrow, and the guy uptown is backed up till the first of the month to do it for you. Or maybe that's just how my life works and nobody else's does. Anyhow best of luck and shop smart and be informed before you buy as best as you can and oh yea buyer beware on used anything.
By the way Mcatshf, nice job on the fitting of components to your lathe.