Do you think there could be a shortage of finance for new ventures? 
Should the government help to provide such finance and if so how?

Do you think there could be a shortage of finance for new ventures?

NO! Look how low interest rates are. That means financing is
relatively easy to come by. Look at the loose monetary policy of the
last five years. If anything, there's too much liquidity.

Should the government help to provide such finance and if so how?

NO! The US has the most efficient capital market in the world.
Financial intermediaries exist to provide financing to new
enterprises. The government can't do a better (i.e., more efficient,
more value-creating) job than the private sector. The government would
do nothing but subsidize money-losing ventures, since financial
intermediaries are constantly looking for businesses to fund.