Since programming language is often tied to programming framework, then switching languages means sacrificing frameworks. That's a problem. Admittedly, it's a form of Lava Flow Antipattern, but it's significant. I'm giving up a useful toolset, and I'm giving up accumulated domain knowledge.
So why do it? Mainly, if the framework I'm currently using can't do things I need to do, or if it's incredibly painful to use. To the extent that someone has neither of those problems, a new language is a cure worse than the disease, whatever its benefits.
Look at it this way... imagine there's a rib joint across the street. It may not have the best bbq, but it's there. Do I walk across the street for bbq, or do I drive halfway across town to get slightly better? I'll take what's there, thank you. Now, if I'm a vegan, I'll get up and go somewhere else.
I think that says more about you than everyone else. I would walk halfway across town for slightly better bbq. Ultimately what is there to life than improving the quality of your experience. The issue is what consitutes better BBQ is completely subjective. So we might start from opposite sides of town and try and get to each others nearby BBQ ribs place. That's just human nature. With respect to "frameworks" some of this tends to be kind of centric to how you program. For the last decade most of my work isn't within any framework because its algorithmic with only a need for string IO and some parsers. Perl 6 for that is the framework.
So why do it? Mainly, if the framework I'm currently using can't do things I need to do, or if it's incredibly painful to use. To the extent that someone has neither of those problems, a new language is a cure worse than the disease, whatever its benefits.
Look at it this way... imagine there's a rib joint across the street. It may not have the best bbq, but it's there. Do I walk across the street for bbq, or do I drive halfway across town to get slightly better? I'll take what's there, thank you. Now, if I'm a vegan, I'll get up and go somewhere else.