Freelancers vs Development Agency
Recruiting freelance web developers can be a good solution for ad-hoc projects (maximum 4 per year). However, if a sustainable business growth is intended then stability and fixed contracts are required.
This is achieved when you have a development company on board as reliable partner. Constant team and price with a contract to secure both. The same freelancers are not always available to do the job for you. So in the end you get a real curve in the ranging of prices/costs per development (caused by multiple developers hired) which makes it difficult to predict potential growth of company profits.
Moreover, it becomes problematic to offer a competitive price for your own clients. Then you might easily get in the position where the market/companies could take over your leads should they set the strategy differently. Markets are changing rapidly, and to be an entrepreneur nowadays is not an easy job.
One should be careful, attentive but more important capable to adjust quickly to trends and changes their business faces.