Learn English – What does “to be already in half pregnant” mean

Here 'right on the line' means 'at a threshhold' of some kind. The exact meaning depends on the context of the article, but the phrase implies the 'others' could go one way or the other.

pencil out is a phrasal verb, and when used in a business context, it means to estimate in approximate figures whether a proposed investment is expected to be profitable. In other words, does it make economic sense or not.

A convoluted example (but it gets the point across):

Net Operating Income (NOI) for a proposed investment was estimated at $10,000 and compared with an offering price of $200,000. The resulting expected cash-on-cash return of 5% did not pencil out because the buyer’s objective was a minimum return of 8%.

In the example you have given, the reason that Chinese investors are continuing to invest in U.S. biotech companies is that there is a shortage of Chinese companies where it makes economic sense to do so.