Yes, the private sector should solely be responsible for developing emerging technologies, because it is only the private sector that can do so efficiently. The private sector is going to stick with what works best. They are not going to award a contract to a relative. They are not going to stick with something that can't make money. They will do a better job.
No, the private sector should not be solely responsible for developing emerging technologies. I think this rest in both the private sector and the public sector. Government should be involved in developing new forms of technology that can benefit the country as well as make life more efficient. To let something as big as emerging technologies rest in only one area make no sense and would only slow future productivity of technology.
Although the private sector can take the lead in developing emerging technologies, they can benefit from collaboration with the government. Many universities and research institutions receive federal and state funding. Scientists should all work together towards solving the world's problems, no matter what part of the industry they happen to be in.
I think that the government agencies should also help in developing new technology also. The private sector usually makes stuff only to help out their company, where the government spends their time making stuff that will be very helpful to the people of the country, so they try to help everyone.
It is great that the private sector is inventing technologies and i would like to see them invent more. I think places like NASA need a lot more funding. But, it is also important for the amateur scientist in his or her garage to be innovative too. Or the professional engineer on her free time.