Large corporations can afford professional IT staff as employees or outsourced contractors; small businesses instead must rely on multitasking staff (or the business owner) that aren’t IT professionals.
If your small business needs just a “brochure” site (one that is largely unchanging and just has limited content) then a site builder service (such as WIX, or Squarespace) may be sufficient. For example, a restaurant really only needs a very simple site that gives addresses, phone number, menu and perhaps daily specials. Take-out can be enabled by just providing a phone number to call to order. Or if your small business is primarily selling stuff, a store using Shopify may be best because it is designed to be very user friendly. If your business has more complicated needs, then WordPress is your solution. You may have heard of other Content Management Systems (CMS), but their popularity is waining as a result of the large ecosystem surrounding WordPress.