Why put forth the expense of obtaining (purchase or rent) hardware and staff to maintain that hardware? Additionally, why put forth the time and expense to write or compose a CRM-like software solution that integrates with voter data, what sounds like a dialer/call center, and "big data" tools (Spark, Hadoop, Tableau, SSIS/SSRS) that probably needs a good 6 months lead time before the candidate even announces a run for office? Also, why would every potential candidate do this every 4 years?

Sounds like a perfect choice for a hosted solution that can be iterated on outside of the election cycle.