First, I think it's important to keep in mind that fedualism is a tricky word at even the best of times. It's used one way by scholars of Marxism, another by European etc. There are few similarities in patterns of land tenures between Europe, China and Japan and there are some pretty smart historians who question whether feudalism can even be a useful term in describing Europe.

So to Africa and the question at hand. There actually is a lot of Africa with a system that has elements of what we would popularly feudalism. For example, Ethiopia long had a titled nobility with many of the privileges we associate with feudal lords (Rastafari name themselves after their feual title, ras) You also have mixed race Portuguese / African prazos (lords) in much of what is today Mozambique and Zambia with colonos (serfs) and chikunda (if you really squint, knights). There are lots of places throughout Africa that had features of what would popularly called feudalism (a term I would recommend being real careful with) .

What I would say is that an important difference between Africa and much of the areas that we might think of feudal is that precolonial Africa was marked by low levels of population density. If a chief or lord became oppressive, a farmer always had the option of moving. This is painting with a broad brush, because some regions of Africa (like Rwanda) were marked by highly organized states, and high levels of population density, while large parts of Asia (much of south east asia, or parts of central India) were not.

EDIT: Ras referred to the title for princes, and some members of the high aristocracy. See comment below.

I broadly agree with the comments of /u/gnikvar2. Feudalism is something of a problematic term, and a few years ago /u/idjet and /u/thegreenreaper7 did an AMA specifically dedicated to unpacking what feudalism was, and whether it was or was not a useful concept for understanding the European middle ages.

Now, to address your fundamental question. In much of Sub-Saharan Africa, land was relatively plentiful and human populations were sparse. You will find scholars like Richard J Reid John Illife who argue that this relative abundance in land shaped African attitudes toward land ownership and group dynamics. That is, since land is abundant, farmers or peasants wishing to avoid the exactions of a greedy elite or chief could simply "vote with their feet" by moving to an area outside of that chiefs control and cultivating land there. In theory, this movement could also mean the rise of new political units (i.e. new chiefdoms or kingdoms), or the reorientation of loyalty of a lineage from one chief to another. (A corollary of this idea is that it would encourage chiefs would look to slavery as a way of mobilizing labor which could be controlled/exploited to a greater extent)

So, with this concept in mind, scholars like Miers and Kopytkoff or Jane Guyer talk of wealth-in-people. The idea being that the amount of prestige an elite person/noble or a chief has is determined by the number of dependents or followers they have through social ties of family, loyalty, or obligation. TL:DR- in certain african societies, chiefs focused on attracting many followers, rather than valuing a system of land tenure.

Now, with all that theory out of the way, I think it is important to mention the empirical example of the Middle Niger region, which was a very fertile agricultural region for the Mali and Songhai empires. Contrary to the theory of an abundance of free land, the Middle Niger was a relatively limited area of rich farmland, and in that region the Mali emperors and their Songhai successors controlled labor by establishing a system of royal estates where slaves farmed the grains that would feed the imperial armies. Here I will quote Nehmia Levtzion's Ancient Ghana and Mali^`

Through taxation part of the agricultural surplus was channeled into paying for the army and the administration of the central government. With the apparent lack of useful technological innovations, production could have been increased only by expanding the cultivated land. This the imperial authority could do only by organizing the exploitation of labour. The rulers established slaves in new villages to till the land and fill the royal granaries.

a detailed account of such slave villages at the time of Askiya Dawud of Songhay is given in tarikh al fattash. on one farm there were 200 slaves under four headmen, and above them the farm chief, a slave himself. The latter was responsible to the Askiya for the supply of a thousand sacks of rice. The farm handed over its quota of a thousand sacks and the surplus was kept by the chief slave who became quite wealthy in spite of his servile condition....

And John Hunwick provides this insight in Timbuktu and the Songhai Empire^2

...Although we should be cautious about accepting the full list of servile peoples ('groups in thrall to the ruler, not free persons enslaved' - qabail ariqqa lahu la ahrar usturiqqu) listed in (pseudo-) Tarikh al-Fattash, -one group, the Arbi mentioned above, is mentioned in what is evidently part of the original text of TF. Both they and the Sorko may have been those referred to as 'slaves of the ruling institution' or 'abid al-saltana, in the pharaseology of al-Mahgilis replies to the questions of Askiya al-hajj Muhammad. The askiya had questioned whether it was lawful for him to retain such groups in a sort of perpetual slavery, and he was told that such persons might be thought of as an endowment (hubus) which it was permissible to hold and inherit. The Arbi are described in TF as palace slaves, bodyguards and grain producers for the askiyas. The term ar bi simply means 'black man' in Songhay, and it may be that the Arbi were descendants of some autochtonous group living among the banks of the Niger whom the Songhay had reduced to servile status, just as other groups had been so reduced (the 'casted' craftespersons -potters, weaver, woodworkes, smiths, etc. and musicians) among the Mande and the Fulani.

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1- Ancient Ghana and Mali by Nehmia Levtzion, 1973. pp 117

2- Timbuktu and the Songhai Empire by John O Hunwick, 2003. pp xxxi-xxxii

edit- italicizing arabic phrase to agree with Hunwick's text.