@esarhaddon , you make a great point. Are you hearing what the engineer heard when they mixed it. That is called the "circle of confusion" and is one of the topics that paper attempts to address. Check out the diagram (Fig. 1) on the second page and then the author states:
Significant uniformity throughout the process is needed if customers are to hear what the artists created. This is the “circle of confusion” shown in Fig. 1. For the system to function sensibly, mixing and mastering engineers need to experience sound that resembles what their customers will hear. Acknowledging that audio systems in widespread use are not necessarily very good, audio professionals in the music side of the business have often used “bad” loudspeakers to check their mixes. The problem is that loudspeakers can be “bad” in countless ways. The dominant characteristics of small low cost audio devices are a lack of bass and reduced sound output capability—a high-pass filter in the playback signal path is a practical way to simulate that. The author’s book [1] (chapters 2 and 18) illustrates the past and present situation in consumer and professional-monitor loudspeakers. Flat on-axis frequency response is clearly the engineering objective for most of these systems