What does "in the world of unicorns" mean?

It is a recent neologism used in financial contexts to refer to:

• A unicorn, in the world of business, is a company, usually a start-up that does not have an established performance record, with a stock market valuation or estimated valuation of more than $1 billion.

(Investopedia)

The "world of unicorns" is the business world of start-up companies (usually tech companies) with a high (1 billion usd) net value.

Origin:

• The use of the term in relation to business was first made by venture capitalist Aileen Lee in 2013 and has become part of the lexicon for public and private investors, entrepreneurs and anyone working in the technology industry.

(www.techworld.com)

"in the world of unicorns", as jargon of the financial world, has already been explained in one answer. The expression is used with a different meaning in other contexts, though.

Unicorns are mythological horse-like figures. "In the world of unicorns", therefore, means "in dreams", or "in an imaginary world"

examples:

• "The perfect mother exists only in the world of unicorns"
• "In the world of unicorns and gullible contemplative readers, there is no point to worryingly questioning eternal truths confirmed by age-old, daily, unalterable, ...
• "Do you guys live in the world of unicorns and rainbows? Never mind, that was a rhetorical question."

As stated in JOSH's answer, a "unicorn" in this context is a start-up company that is valued at $1 billion or more.

Every investor is chasing something shiny, they do not care for the ecosystem at all.

The author is saying that investors are so focused on chasing unicorns, that they neglect their "ecosystem", or other start-ups.

In the world of unicorns it is really hard to see any other animal.

In other words, investors typically only invest in start-ups that they believe will become unicorns, which prevents start-ups that don't look as promising from receiving enough investments to prosper.

In a world where everyone is looking for the next billion dollar opportunity, other opportunities get neglected.