For instance, "parser generators" like yacc, bison and all the rest are absolutely awful. One feature they miss is that you should be able to make a small revision to a grammar with a small code patch. (Say you want to add an "unless(x)" statement to Java that is equivalent to if(!x)" - ought to be 50 lines of code not counting the POM file.)
I think a better parser generator could open up "compiler programming" and "meta programming" to a wider audience and get LISP fanatics into the 21st century, but it never happens. Anybody who understands the problem enough to solve the problem will settle for a half-baked answer; the labor input to go from "the author can use it" to "revolutionary new parser generator" is a factor of 10x and there is some risk that people still won't get it.
Programming the AVR-8 Arduino it's hard to miss the conclusion that "C sucks" but anything really better (say Supercharged Pascal or a Miracle Macro Assembler) would take a huge amount of fit and finish work to make it something that would really beat C. For pedagogical purposes you can argue that C rots the mind like BASIC but you can't argue that learning C is a waste of time.
To make a profitable business out of any of the above seems almost impossible.