This would end if Trump declassified, which he has reportedly declined to do regarding the redacted portions of the FISA warrant. Impeachment rulings are unlikely to be successful in the Senate. So what recourse is there? If the House votes for contempt against various individuals, they may be forced to testify, but only that they are invoking their 5th AMend right against self-incrimination, they don't remember, they have to check with their records, superiors, etc.
Haspel was said to be the head of UK. I don't trust anyone in the CIA. What about human and drug trafficking, illegal wars? Concerns go beyond the 2016 election, of which she likely has knowledge.