In theory sure, but in practice there are ways a company can offload this burden onto the consumers with minimal impact to their bottom line, like raising prices in an area where there isn’t any competition. Hurting the competitiveness of a major player will likely negatively impact the whole market because it will allow their competition to charge more as well. Most likely it won’t impact large shareholders whose portfolio is diversified enough, as they can own stake in all players on the market simultaneously, it might even be good for them; less competitive market -> higher margins, shareholders with equal stake in T-Mobile, Verizon, AT&T win regardless of any one company’s performance.