Vintage (pre-1989) investment = Mikan, Russell, Chamberlain, Alcindor/Jabbar, Magic, Bird, Jordan, West, Baylor, Robertson, Erving, and the better key rookies every year.
IMO the main thing that depresses basketball cards (except for the investment ones) is how few cards there are to collect. From 1948-1968, there were three mainstream sets: 1948 Bowman (72 cards), 1957 Topps (80 cards), 1961 Fleer (66 cards). That's it for 20 years. Putting them together is expensive AF because of the rookies and 2nd year cards (you're lucky to get a beater 1957 Russell for under $5K) but assuming the money is not an issue, you are done with just over 200 cards. Even hockey has many more mainstream issues. That leaves a variety of team issues, regional issues and one-off issues in multisport and foreign sets, many of which are uncatalogued or under-catalogued, and many of which are HTF or downright rare. Some are really cool cards:
But many are ridiculously rare so you stumble on them rather than plan to collect them. It is a fun but slow and challenging pursuit.
The dearth of mainstream and rarity of regionals also makes rookie cards difficult to assess. Case in point: Jerry West. The actual logo man. 1961 Fleer, right? Nope. 1960 Kahn's and 1960 Los Angeles Examiner, and 1961 Bell. Finding the Kahn's, very, very tough. Finding the last two, impossible. Alcinor/Kareem: 1969 Topps. Or is it 1968 Mira Tuttosport (very tough). Jordan: 1986 Fleer? Well, several 1984 and 1985 Star issues (est. 2500 legit sets made)
and 1985 Merchante Spanish issue (same as the Magic below; not that tough except in unstuck form--meant for albums--but tiny pop compared to mainstream), and also a 1983 ACC board game issue (rare).
There are also foreign cards that fill in the wide gaps in domestic issues, but these also are hard to find and not well understood.
Another factor is lack of cataloguing and readily digested and updated encyclopedias. I had to buy an old OOP Sanchez magazine guide simply to get checklists of some of the regional issues. Many of them simply are not catalogued, so you have to have some researcher in you to collect and even then you may find yourself at a dead end or making conclusions from context and materials. Take this one:
Wilt Chamberlain PC sized photo card. The image is taken from a team photo session that yielded one of his team issue publicity photos ca. 1962-1965. It is literally the same shot, just from a split second earlier. But if I didn't know what I was looking at because I had the TI, I wouldn't have known what this was when it popped up. That lack of information and rarity depresses price relative to the mainstream issues and even the better-understood foreign issues. That is ending but it is still a field ripe for systematic analysis, cataloguing, and potential profit.