A question I have been asked lately is "Can't I just use Wix?". Well, yes, in the same way you can make your own wedding cake. Web development goes further than getting a website released with a bit of content and waiting for results.
Wix, and other site builders are a cookie-cutter approach. There is a ceiling in terms of functionality and features. By using it, your website will only be as good as the many others who are using it. You want a lasting impression from your website and certainly the tools to give it the best chance possible.
Web development is complete in the same way your hair is styled. It needs ongoing attention to keep up and maintain a position where it generates interest. Site builders limit your potential and will often cost you more in terms of lost leads than if you hired someone to produce a tailored solution. In comparison, Wordpress (to pick the most popular CMS) is potentially unlimited in capability and flexibility.
For sake of argument - for anyone of a basic calibre in the web industry to produce the equivalent result of a site builder, they would install Wordpress, pick one of many tens of thousands of available themes aimed at your industry, and then add some content. Very simple stuff, but you need more than this. It still has the problem of not being designed for your business needs. At least though, a competent developer can near-limitlessly tailor this for you as we have complete access to the codebase. We can ensure it is SEO-friendly, we can support you in terms of content and certainly theme it as good as anything out there or better depending on requirements.
Site builders aren't "industry killers” if you think about it. They should help the industry by forcing designers to raise the bar in terms of web design. It allows businesses to get a taste for the web and to get a better idea of their requirements before investing in it, though this does often have a draw-back. There are businesses out there who have failed to get anywhere with this approach, and are instead put off from investing in it.
You get what you pay for. Web development may seem expensive, but compared to TV, radio, billboards, magazines, and other such advertising, it has much greater potential for reaching your target customers, much more flexibility, and capable of being seen on any device with an internet connection - something in this day and age, your customers have multiple of.