The message you deliver at a presentation may physically only be received by a few people but one should consider that it has value for a much wider audience. A research discovery, a new business plan or an effective audit are not simply of value within that physical space. The knowledge or insight should be carried from that place for it to be of wider value. Your presentation however must only be for the audience present.
The p1 of the presentation should be a message, not a data download. Its purpose is to convince the audience of your idea. It is not about delivering all the data related to this idea. That is much more efficiently held in a textual format. A huge volume of factual information will never be retained and attempting to deliver it will obscure, rather than clarify the message. It is a clear message that will be shared with a wider audience, not isolated data.
The p2 of the presentation should support the p1 and its delivery, p3. It must not be designed to add additional information, references, complexity or a means of recalling the detail of the message. This will only obscure rather than clarify the message. Similarly the delivery, p3 is about the audience. Simply reciting data is of no auditory interest to an audience however factual or detailed: the audience is seeking engagement with the speaker and the message. Complex slides or a speaker who reads their slides do not aid the spread of the message.
An effective message will encourage the audience to seek more detail. A supportive media will allow the audience to focus on the message as it is delivered and an engaging speaker will increase the reception and retention of that message. Concentration on the delivery of a presentation solely for the audience present will ensure the message reaches a wider audience.