Funny you say that about gundam, a couple weeks ago I decided to try to get into it from the beginning and I had to jump through hoops.
The original trilogy just happened to be streaming free on the gundam youtube they periodically rotate which series is there so I got lucky. Gundam origin was on hulu, zeta was no where to be found, it was on the gundam yt but got removed. So only physicals for that and it's going to be pricey to get the whole series.