The best performers in today's market are decidedly not short-term focused. Amazon and Netflix barely turn a profit, even though they could. Ditto for Tesla (well, maybe they couldn't atm even if they wanted to). The entire tech sector, which has been on a tear, is similarly long-term focused. Snap's stock, for example, isn't being hit because it's not profitable, but it's getting hot because its user base is plateauing (i.e. negative long-term signal).
Do a lot of (most?) companies focus on the short-term? Definitely! But that's rational behavior even from a societal resource allocation perspective. Imagine you're Walgreens, Target, P&G, Kroger, JCrew, or one out of another thousand "boring" (i.e. low upside) companies (like most others). If the upside at your company is limited, why throw money money at "long-term" thinking? It makes more sense to maximize profits now and return profits to shareholders who will in turn invest in the Amazons, Googles, Teslas, etc. who have the technological infrastructure and human capital to generate better returns per dollar of long-term spending.
The end result (which is happening) is that most companies by volume focus on the short-term because most companies in the US are working in a mature market with a well-explored product and have limited upside, while a small number of companies with large upside get a disproportionate share of investment.