People aren't starting competitor businesses because the hassle has become astronomically expensive, also largely due to rent seekers[0]. You need a space, but real estate is absurdly inflated. You need trained employees, but education is absurdly inflated and also poorer quality for the baseline. You need to pay a living wage and give healthcare benefits to attract labor, but cost of living and healthcare are skyrocketing.
Ultimately the influence of rent seekers has grown and the category of people who can take risks by starting a business was the first to collapse, leaving only the wealthy who don't care and the people who can't risk their own survival.
Then there is regulatory capture in some markets. In this case:
You need a street legal product, which takes certification You probably need multiple firefighter associations, which takes not only meeting criteria but politicking with associations (don't know about firefighters but some associations are themselves captured and limit approval to their friends/connections).