It's not impossible to fully breastfeed a baby, or give them a combination of solids and breastmilk if you are WOH full-time. I did it with my first child - he didn't get any cows' milk protein until he was over 9 months.
If you are motivated and organised, then it's fairly straightforward to express milk (and for those who don't get more than a few drops, it does increase with practice). If you are worried about supply, then you can make sure that you have unlimited BF in the evenings and weekends. You may have to change how you do things around the house - it's a case of priorities for you and DH.
If you leave a young baby, they are likely to sleep most of the day when you are not there, and save their waking moments for when they are with you.
For babies who are on solids, then it's fairly easy to keep their tummies full this way, and even easier if they will take EBM.
Work does not automatically mean bottles of formula.