Yes focusing on say for instance "lawn mowing" if that is your focus you are wrong unless you are a nationwide company. You should instead focus on "lawn mowing anytown anystate" This will have less competition than lawn mowing. focus on where you get the most of your work or the area you want to work in. for instance if you live in say Chino but you want to work in Beverly Hills, you would then focus on "lawn care Beverly Hills CA"
The big SEO companies do have teams of people but they also have either purchased or written software that allows them to partially automate the processes. I say partially because you can not completely automate the process. I don't work by myself, I have others that are experts in their specific area of SEO that I count on to complete the work. That is how all the SEO companies should work. Not with one person trying to do it all. It is impossible to know it all.
Don't get me wrong, there are a few exceptions it seems but they are normally working on high dollar accounts(or for Google...
Here is an example. I have a list of over 6000 directories and say it takes an average of 2 minutes to sign up for the site (before you can add your listing) that is 200 hours of work and then say you add 1 minute to type in all your company data now we are at 300 hours to do this manually.
With the proper software you can cut this time dramatically but it is not fully automatic. You still need human intervention. This is where the SEO companies come in. They have the software and the people dedicated to each function.