Bismillah, 

Asalamu Alaykom, 

it isn't necessary for everyone to go hawza although it is obligatory upon some to do so. Whether one is working or studying their secular studies, there is so much Islamic content online for one to learn from. One needs to see what their overall ambitions and goals are. If you feel you want to fulfill a secular career while also gaining Islamic knowledge, then this can be achieved. Yes, it may be at a slower pace, but it is possible. 
 

There are many great online hawzas which will teach you many of the same books and sciences you would learn abroad in hawza. 
 

Some of these online seminaries I can recommend are Imam Sadiq Online Hawza and Hujjah seminary. There are also other online shia hawzas too which you can study at your own pace and fit in with your schedule. 
 

May Allah grant you knowledge