The "why," if not the "how," of innovation is simple: it is the purpose, reason, or cause behind whatever adaptation, improvement, or invention is needed and successfully applied to beget from scarce resources valuable outcomes that meet explicit or latent needs. Innovation is something that is new, capable of being implemented, and has beneficial impact. Insights from biology, geography, and sociology confirm little distinguishes what impelled our Neolithic ancestors from what drives modern man. And so, one can expect a continuing flow of innovations in the future, in what direct and indirect forms (e.g., products, services, models, and approaches) best help meet the challenges the world faces, the list of which is daunting. (Whether there will be more or less does not really matter, although I surmise we will have to innovate more often.)
PS: A select list of the worldwide challenges we face includes alleviating poverty; mitigating and adapting to climate change; ending abuse of natural resources and the environment; cleaning up environmental pollution; dealing with natural disasters; countering medical challenges, e.g., pandemics; encouraging disarmament; coping with security threats; accommodating nonstate power; handling failed states; tapping capacity for social action; allaying frustration among minorities; confronting violence; identifying global rights; building a global rule of law; evolving regulatory and institutional frameworks to contain global financial and economic crises; optimizing international trade; managing mass migrations; employing human resources better; and optimizing knowledge.
First, I presume that you mean radical innovation when writing "new innovation". Otherwise, new/novel to whom you might ask yourself.
I had the same question in mind the other day. It seems like every major innovation highly depends on multi-disciplinary collaboration between many different stakeholders, which reflects the multi-faceted reality of the phenomenon. This calls for less radical innovation, because individuals face a hard time in creating radical innovation with the scarce bird-in-hand—you are much more dependent on external knowledge flows. Although a new technological change can tilt and turn the game and paradigm, it is interesting how the possibilities of technology also can be a barrier to innovation. To answer your question, it would be interesting to look how the business cycles and the technological pushes have influenced the need and effort for doing innovation historical in times of recession and recovery. Thence, you might be able to predict the level of innovation in the future.
There can be different answers to this question, depending upon whether you mean radical or incremental innovation, what type of innovation (product, process, etc: its six-seven of them), and a more general thing whether we are talking about "technological" innovation or any other. I presume you mean technological radical and product (the most common understanding of innovation). Radical innovation comes in circles and any itechnological invention does not become innovation before a cysle is closed. It ususlly is linked to atechno-economic paradigm. There is a lot to say here, but see the legacy of Chris Freeman and Karlota Perez, plus the work carried out in SPRU Sussex. My personal opinion, yet intuitive, is that radical (technological) innovations will become more freqent in the future and inncremental ones will proliferate as long as the 'products' are able to make money for the sellers. I argue for this (hent' done a ny special research, however) having in mind the rapid everyday advances in technology, inmany fields (electronics, bio-sciences, etc).