Let me answer this question from 3 different perspective and on a case to case basis to make it specific.
1. If you have a website
The answer is no, you cannot get enough clients by just having a website. Forget about enough clients, chances are you will not even get a single client from a website by just putting it in online.
A 4 to 5 page website that doesn’t offer any value will not drive any potential clients. A website is not doing anything for you unless people find it useful and want to visit it.
If you promote the website to the right audience on Google Adwords and Facebook, it may drive some potential clients. Again it needs good budget and planning along with expertise in PPC marketing.
2. If you have a blog
A blog is definitely more useful than a website even if you aren’t regularly writing for it. Add useful content as and when you can and potential clients can reach your blog when they search for information related to what you have written.
As readers find content useful, they will be more than happy to hire you for their custom needs in future.
It need not be a web design or development blog and can be anything can be useful to others. If it is helpful, they will get in touch with the blog owner for any further requirements.
3. Why only focus on website or blog?
Why you want to be focusing only on website or blog for clients when you can have clients from freelancing websites like Upwork, Freelancer.com or PPH. (Here are 9 Best Freelancing Sites). There is an opportunity to find clients in those websites and it is never wise to ignore them.
My blog is a source of clients but I have never switched off Upwork (And Elance). I use only Upwork over other freelancing sites because I have many regular clients and has to reject many project invites even in Upwork.
So yes a blog can definitely drive you clients but not a 5-page website without any marketing but never underestimate other channels for potential clients.