I agree with @Thomas S. His statement includes many more (hidden) aspect such as, for instance (to name just one) less costs (= less money "wasted" = more money available) related to the transactions: every building you buy will have a base amount of costs associated with that transaction. In essence it makes no difference if that building has 1 door or 12, the costs of buying are (certainly when spread out over the doors) more or less the same. This is even more true if you are financing due to the added costs from that end. The fewer transactions the less costs.
On the other hand, the more doors, the more money should come in. Whether that particular multiplex ultimately is a good deal is, of course, a totally different story and obviously something you need to figure out during your due diligence on such a property.
Then again, as always with real estate, this depends on the market you are investing in. Some people swear by SFR, others only do multi-units, others only do Condos/Townhomes with an HOA etc. etc. You need to feel comfortable with the property you are investing in, and you need to understand that particular business to be successful: owning a multiplex will be different from owning one or more SFR. Not earth-moving different but still.
And since you need to generate income it means that you do not have enough money available so this in turn means that you will have to use leverage to increase the amount of doors you own. And that is, with respect to your goal, a good thing. At least in my and Greg's and other people's opinion. ;-) Good luck. I myself am trying to achieve what you are striving for!