The big company steamrollered all the small competitors with its low-price strategy.

steamrollered 是动词 steamroller 的过去式。steamroller 由 steam（蒸汽）和 roller（滚轮）组成，原指"蒸汽压路机"，引申为"以压倒性力量推进或压制"的意思。这里比喻大公司像压路机一样碾压小竞争对手。