Actually, a mobile device like the Yaesu FT-891 is not comparable to a portable radio. The main power consumption is much more due to the power amplifier and the increased circuit scale. The energy consumption of the displays is secondary. However, the difference between the Yaesu FT-818 and its predecessor is rather marginal and therefore at best a kind of product maintenance. The expectations of the consumers were unfortunately not fulfilled again. Under these circumstances, you can also buy the Yaesu FT-817ND with the required filters and the TCXO-9 at a package price.Part of the perceived problem with the FT- 891. The bigger the display, the more juice it draws. Not so great for portable, but I love mine for mobile.
I think that several factors play a role here, the existing parts are only a partial aspect. The managers at Yaesu know very well that there is currently no product on the Western market that offers all the frequencies in this performance class at a relatively low price. The last word is always the consumer, as long as the sales figures are moving at this altitude, Yaesu doesn't seem to need any action.A lot of companies will build an item with the goal to come in at a certain price point. No matter what the outcome is. Maybe that's what happened here?