OK, thank you taking time explaining the confusion.
It's NOT that my powering sleds are better than your current battery solution for <7 hours use where recharging is easy after each session. Yes, they far more reliable than rechargeables solutions, but for non-professionals, reliability is usually not so important to consider paying a premium for custom made batteries priced as required to produce in this fashion.
While I have been producing these special battery sleds since 1992, some of the high reliability materials are no longer available in USA (or anywhere in small affordable quantities) needing to be special large quantity ordered at cost of thousands $.
So I have to charge both for my time and materials to keep this product viable.
I do sometimes get thanks from sled customers (mostly university natural sounds and remote ambient sensing project managers) for making possible/practical remote field project recording logistics using commonly available deck models that you and I also might own.
So, what I offer for field recorder powering is the most reliable, lowest weight/size, and longest running solutions currently available on the market that's NOT really comparable with cheap, low reliability, short runtime products meant for different user requirements, and mostly useful, and well worth the cost for those doing film/video/project sound and nature/natural sounds documentary recording in remote places where very long running times, and/or recharging batteries is not desired or impractical.