It's figurative language. Literally, a plow is a large, powerful tool for pushing dirt or snow aside, like one of these:
An agricultural plow forcefully pushes straight ahead, leaving a trail of turned soil in its wake.
Metaphorically, "plowing through" suggests overcoming resistance or difficulty by brute force and sustained effort rather than elegance or subtlety. You push straight ahead with great effort, regardless of obstacles, like the oxen in the top picture. Most relevant to the headline you found, "plowing through" can suggest destroying something or using something up, like what happens to the ground or the snow.
The headline suggests that the founder spent the money continuously, without a break, in a big effort to make something happen, like the oxen or the truck exerting a strong force as they move steadily forward. The headline also suggests that the founder received little or no return on the investment while he was spending it. The money is now gone, something like the soil or snow that a literal plow pushes aside.
The headline suggests to me that the founder might have wasted $150 million through bad decisions, but not necessarily. It might have been wise to spend so much money without a return on the investment, or perhaps it's too soon to tell; you have to read the article to find out for sure.
Source for the drawings of plows: Merriam-Webster Learner's Dictionary.