MIT study (long PDF) on geothermal energy suggest 100GW can be generated by 2050. $300-400 million over 15 years would need to be invested in research and cost reduction for 15 years before geothermal would be cost competitive. The 100GW by 2050 figure assumes $800 million to $1 billion over 15 years in investment in research and development (mainly prototype development and refinement).
So Geothermal is not ready now. I think the investment and research should probably be spent so that another added option is developed.