Do languages eventually get better over time? If that's true, I would be expecting some fossil languages to become less attractive over time as living languages like python and ruby become "better" for your given needs.
Current Lisps are so dissimilar to the first Lisps that they're hardly the same language anymore. Really, the Lisps form a family of languages. If you can argue that Clojure is just a "better" Lisp, you could just as easily argue that Go (or C#, or Java, or whathaveyou) is just a "better" Algol.
Well, now you have to define better. What makes one programming language better than another? For some people, a better is a more elegant mathematical model. For others, better is popularity. Still others favor raw performance, portability, or ease of learning.
Someone who absolutely loves parentheses and capital letters would probably favor LISP 1.5 over Clojure.
I don't think there's any general law for whether they do or don't.
On one hand, I can definitely look at C# right now and see how it is a vast improvement upon C# 1.0. I'll even go as far as to say I would probably refuse to write code in C# if it had not become what it is today.
On the other, I think you can only really change a language up to a certain degree before creating an inconsistent mess. If trends in the future dictate the need for a shift in paradigms, the extent to which existing languages can accommodate this shift is probably limited. I mean, you can often incorporate features that are based on the new approach to thinking about a problem, but once you start changing the core semantics of the language you're probably going to be better off with something completely new.
Well the thing with languages are that they are always better, under some circumstances, than some other language (maelstrom and brainfuck excepted, they are no good under any circumstances) which are in turn better than others, under other circumstances. Nobody would choose ruby to write a kernel or do embedded programming. You can find better languages than C to write a web service in.
While languages don't get better over time they do change which means that there are more of them, which means it is more likely that you will find some that suit you.
