So yes, content is playing a major role in website ranking this is because in the initial phase of the SEO the website owner used the repeated content in all over the pages of the website or copy the content from other niche website and paste in his website which was a duplication. due to this the website which have not any quality in his design, development and content was coming in top 10 in search results. To recover from this issue Google SEO department launch Google Panda algorithm which directly deals with content of the website and the content to posted on the third party website.
So come on the main point that you asked - length of the content is matter but it is totally depend on the quality of the content, Engagement rate and User friendly. If you are writing a content of 2000 words in the website but it has not high quality then user is not engaged with your website, results it gives you low ROI.
But if you have everything in your content and write to keep in mind your audience requirement, what they want, whether your content is 2000 words or 500 words. If it gives the clear vision to the audience which benefits you in ROI and yes boost your website in SERPs.
One more thing I want to cover here, Content is also helps to make your website authority. once your website has good authority, lets say it is above 80 out of 100, then you will always be on top. You can see that in the search results , there are lots of the website which have very less amount of the content in the home page but they always be on top 10 in SERPS.