In another thread I received this news from Eddi40 :-
Just so you know i spoke to an electronics supplier today whos very knowledgeable as a supplier goes and he says in 18 months time the CD4000 series are being phased out with no equivalents being hinted at, so buy em while you can guys cos they wont be around much longer
It is a typical life cycle chart that shows the CD4000 family was introduced in the 1970's and is now in its decline phase. Try to look at it again with that perspective.
Read it again. The CD4000's were introduced the 1970's. The dates shown are the dates of introduction. The graph is a generic product life graph. I think you are taking the word, "introduction," in the wrong context. It is not a simple XY graph.
These devices are made by so many different semiconductor manufacturers so I wouldn't lose any sleep over it. Nothing on the market can make anything close in terms of wide supply voltages and current. I keep gettting told at work that a CPU could do the same functional logic. Maybe but not at 15V with a current of micro-amps.
I can easily get any logic circuit through our QA dept and design reviewers. As soon as you put a micro in the equation then there are reliability issues brought up even with solid 8051 cores/core implementation/C compilers and assembler bugs.
I personally think the TTL LS series would go due to their limited supply voltage, but you can still buy them from RS and Farnell/CPC.