It's a proven fact that it's 7 times less costly to convert existing visitors and customers than finding and attracting 7x more search traffic.
The amount of effort involved and time needed to achieve a 700% increase in visitor numbers is not impossible but almost prohibitive in an acceptable timescale.
Make the most of existing search visitors
Why let them escape?
For very little extra effort or cost (see graph) working on your site's content to engage more, better provide the information they were searching for will keep them on-site longer and invevitably raise your conversion rate.
Every business has fixed costs and overheads regardless of the level of sales or business it does. Focusing on increasing your conversion rate, by testing & analysis, and not wasting the effort in attracting existing visitors will increase your cost of sales or customer acquisition but the rise in profitability will be the real justification and reward.