Price inconsistencies are primarily because companies sell half assed solutions.

Company A sells the PoS system, it's CRM, database, management seats and support.

Company B sells the e-pricetag system, its CRM, database, gateway (most either use Bluetooth or a custom 802.15.4 based protocol, ZigBee but not really), management seats and support.

Since there's literally hundreds of Company A's and Company B's, and there's absofuckinglutely no standard for either product, it's a hit and miss if the systems can actually work together - primarily because the acquisitions aren't done by involving engineers/experts who pick the best fitting system but by having some dumbass VP or C-suite who knows a guy who knows a guy (and most likely there's a nice kickback chain), and another dumbass middle manager picks the other, compatibility being potentially the least important aspect.

Then you have the clusterfuck of systems not working together, and needing someone to manage the PoS, someone to manage the price tags, and either a C-suite's 15 year old nephew who's a "programming genius" (managed to prompt Claude to write a calculator app he showed off once) gets some nice money for writing a godawful bridge between the two that kind of works when the stars align right (and breaks after three months because both systems got updated), or there's an actual underpaid gofer whose sole task is to keep the databases in sync.