Marketing is not a race. If you are in business, you should know and understand that marketing is a continuous process. If there is an end to marketing, there is also an end to revenue growth, new customer acquisition etc.
When it comes to marketing online, I've met a lot of business owners who have an online presence, but who aren't happy about it. They have "tried everything" from SEO to social media and nothing's worked, from their perspective. They're tired of the cost, and they're frustrated by the lack of results.
To be fair, that's a very reasonable outcome. If I asked you to spend $5000 and not have any measurable return on investment (ROI), you'd probably walk away. I would too.
The word "measurable" is important though, because you CAN measure many, many things when people are interacting with your online presence. On your website, you can use your analytics to see what people are clicking on and how they're coming to your site. You can use heat mapping to see where people are focusing their attention. Any reputable email marketing software will tell you your open rates and track what people click on in your messages. Social media tools give you metrics showing you what posts got the most attention.
Then the hard work begins. Analyze. Investigate. Uncover reasons. Ask questions. Tweak your site, your content, your next post, and then do it all over again. If you want better marketing, you need to have a better system.
Nobody can say for certain that creating and implementing a robust inbound marketing plan is going to be a goldmine of lead generation. However, it is true that not doing anything will very likely be worse for your business' lead acquisition. Even if you put together a plan and start implementing slowly, you'll be better positioned a few years from now.