There are two kinds of technology that would make space exploration easier.
The first will come without government support. Anyone that figures out how to make a lighter solar cell, or how to deliver payload to earth orbit cheaper than their competition will do well without help in existing markets. If you can build a solar array that is lower mass for the same power, plenty of commercial ComSat companies will pay extra for that.
The second is more difficult. There are technologies that NASA would really like to have: more powerful electric propulsion, or an Advanced Stirling Radioisotope Generator, but there is no current commercial market for these. Aerocapture beyond Earth orbit would also be good to have. It would be very valuable to have a rotating orbital habitat to simulate the term long effect of Lunar and Mars gravity on living terrestrial organisms like us.
We should spend more on advancing the second kind of technology.