There are countless programs to make web pages, however all of them use programming code that is not optimized for your web page to load with the proper speed and it is clear that not everyone will be able to debug that programming.
To optimize the loading of the page requires a deep knowledge of programming, that is why, although there are many charlatans who offer SEO positioning will not be able to fulfill what they offer.
For a web page to be positioned its programming must be very clean, and minified so that its load does not present delays or excessive work to the server in which it is hosted, an impeccable programming can only be done by an expert programmer. That is why programming is a key point to achieve the good positioning of your page and not all developers have one.
There are tools that allow you to see how well optimized a page is, if your developer has no idea about this better look for someone who does.