So you can not see why someone would pay for SEO?
1. The time factor. Yes you can do all the things for seo on your own but when will you have time for your family? When do you work on seo, during the day when you should be operating the business? How about at night when you should be spending time with the wife and kids? Maybe you can do it on the weekend when you need to take care of your yard?
2. Here is another one. How long would it take you to build 100 quality links to your site? I mean from like topic sites not sites that you can submit on several different pages. I am talking about unique domains and these have to be a page rank of 3 or above on the domain. I would say it would take you a better part of a week to find those sites. Now what if I could do that for $30 to $50? Would that be worth it? Remember you do not want to use those same domains for the next 100 so it starts all over again.
I do sell SEO services but I look at the whole picture and see what would be the best investment for the site owner. I am doing a site right now where I told him the best investment would be to reconfigure the site. This would give him the best ROI.
I don't know if the people that have contacted me from this site will chime in but I told them the same thing. A new site will help them better for rankings than any link building campaign. This is because their local competition was not that heavy so they did not need a lot of link building.
I proved that in another thread here with "lawn mowing gulfport" by adding a page to one of my sites and posting a link to it here. Within 36 hours it was on the front page for that search term. But try the same thing in Chicago, Denver, Los Angeles, Seattle or any other metro area and you will be disappointed.
Some will say narrow it down to sub cities. You can do that around Seattle with Redmond, Kent, Federal Way etc but you still have Seattle with millions of customers. Same thing with Chicago and LA etc.
I know people that build beautiful web sites and charge accordingly but on the SEO side of the design they could not rank for "purple turds".
Your method will work in smaller markets but there are thousands of sites on the web that are great on design and seo that never get found because the search engines don't care about them for those keywords.
Here is an example:
Google "woodworking" and way back on page 16 you will find www.scrollsawer.com
Now looking at the title and description, they are trying to target "woodworking" as a keyword phrase. I will admit the site could use some work but overall it is not bad. And the fact that the keyword searched only has a medium competition range which means that about half of the searches on the web have more competition and the other half have less competition.
Now according to your theory, this site should be all over the front page. After all the site was registered on Jan 4, 2000 which makes the site a little over 11 years old.
Oh and "woodworking" is searched 823,000 times per month world wide and 550,000 times in the United States alone.
This is why people pay to have SEO work done. It is easy to rank locally in most cases but if you need to rank nation or world wide it is going to take more than just building a site and crossing your fingers. Even locally you need to do some link building but that is not as intense as a wider geographic ranking area.
I am not blowing smoke here guys. It is very hard to get ranked in some areas. It is not just one thing that works to rank your site but the combination of a number of things.
I am going to start a new thread for a FREE item to help you see the light.