One basic and significant differences : Clams coin's distribution was based on number of wallet/address (of BTC,LTC and DOGE) whereas bitcoincash is based on how many of BTC. Probably this difference alone would have led devs not to go based on CLAMS' concept. I am not a technical expert to mention out why we have not seen any CLAMS-2 yet I assume we may see one in near future too.

Tell me more about Clames because the current monolithic block-chain as it is stored on 20,000 nodes
simply does not scale and it needs breaking down into a tree structure

Transactions per second
BTC = 7 
ETH = 15
IOTA =100 (Tangle)
VISA =25,000 (Semi centralized, 500 time less CPU used as BTC)

The writing is on the wall and in any-case Lightning with it's hubs
becomes Semi centralized but lets the bankers in by the back door
so i am looking for something that is radically new that will scale

Segwit2x fork might help for now and spread some of the load but
still the design is wrong

See https://www.youtube.com/watch?v=UYHFrf5ci_g