The question is why do you need to know everything? You have a good base of knowledge now (presumably). You then add to that base whatever your employer requires you to know. And you will learn most of that on the job. Learning other things will be valuable but only to you and future employers. Your current one wants you to produce what they produce.
If you feel the need to learn everything ask yourself what company uses everything. The answer to that is very few to none. If you were thinking that you need that because you were going to freelance then the question I want you to ask yourself is, what project could you possibly be involved in where a single person needs to know every single thing about web and mobile development. And if you find that project then run away from it because you will end up a burnt out husk trying to do the work of dozens of people.
In my case, I am employed by a company that makes serious games using Unity. When I came on board I had never used Unity nor had I written a single line of C# (our language of choice). So I learned those. There were no requirements to learn web or even mobile development at the time. So I did not study anything about those. A year later I was chosen to be on a project involving Unreal. So again I learned how to use Unreal and the syntax for Unrealscript.
Companies hire new grads knowing that you still need to learn. Good ones will give you that opportunity. If you still feel that you need to learn more then that is what your spare time is for.
Happy reading ツ