We plan to incorporate time/estimate reports in TestRail eventually (hopefully later this year). In fact, we plan to use both estimates and actual test times to calculate forecasts for how long a test run/plan is going to take. Since TestRail learns more and more about tests over time, we expect those forecasts to be extremely accurate.
However, you could calculate your own estimates in the mean time. It’s true that the CSV files don’t contain the time data (this is because there can be multiple test results for a single test and CSV doesn’t support hierarchies).
We do include test timings in the exported XML files though and you could use this data to calculate the test times. You could alternatively run a database query to get this data. We will look into adding an aggregated time value to CSV files and I have added this to our feature request list.