Keeping kosher only makes sense
- if you enjoy giving your money to rabbis and mashgikhim with no real job skills.
- you are a rich modern orthodox
- you an ultraorthodox on government assistance
In either case 1, 2, or 3, you have better things to be bothered with than the cost of food.
Now, assuming you are neither 1, 2, or 3, keeping kosher makes no economic sense. It's too damn expensive for the average Joe who works hard but isn't rich or isn't a welfare taking ultraorthodox.
Especially when you consider the fact that kosher inspection orgs cut corners with nonkosher ingredients (OU scandal as documented by Failed Messiah).
And kosher inspection orgs unethically weild their power to revoke certification from restaurants over not following orthodox mores that have nothing to do with food.
Food prices are high enough. Kasharut "workers" should get real jobs.