I think this depends on the nature of your company, and how you hope and expect to be discovered by potential new customers.
For the vast majority of businesses, ranking highly on search engines like Google will prove very valuable.
However, it can be very tough to rise the ‘natural’ search rankings – i.e. the first slots that aren’t paid for – so for some startups, their marketing budget might be better spent elsewhere.
For instance, in highly-competitive consumer categories – travel, for example – it’s very difficult to get ranked on page one unless you’re a Tripadvisor or Expedia.
In such instances, startups will get a better ROI by investing their budget and resources in other forms of marketing and customer acquisition initiatives.
A solid search engine ranking can actually be a happy consequence of investment in other marketing initiatives. For example, a high-quality, regularly updated blog and articles on major websites linking to your homepage will result in an uplift in your natural search ranking.