I'm sure there are a lot of people still developing for Magento 1, despite its end of support on December 18th. There was a significant forum post on Magento's website reviewing the details of the end of support and discussing how it would affect developers.
The difficulty of developing in Magento 1 and how useful it is to keep doing so has been discussed extensively since the announcement. A lot of developers are still working on projects in Magento 1, as they consider the challenge of migration to Magento 2 too great and costly to justify the switch.
It’s worth noting that some third-party libraries and modules for Magento 1 may no longer be maintained, so it’s a good idea to research those before you begin work on any projects.
There are a lot of pros and cons, and ultimately each developer needs to make the decision for themself, but there are a lot of resources online on the Magento 1 forum and Stack Overflow to help you make an informed choice.
I hope this answer helps.