I worked on code, protocols and a chipset for ATM and it was very, very quickly obvious that in the LAN environment ATM LANE was a total mess and the supposed driver for LAN ATM was desktop video conferencing which "required" QoS. At the time the competing LAN technolgies were 10Mbps Ethernet and 16Mbps token ring. What became very, very obvious was that 100Mbps Ethernet with switches was doing to win because... known technology (for IT departments), same cabling. I was just a peon but watching upper management talk about ATM being the future was very instructive: they weren't close to customers.

You might enjoy this 1996 presentation from my old employer: https://www.slideshare.net/redpineapple/atm-sales-from-madge...