1. In the first half, IRCC did not issue any ITAs for a few months. This is reflected in the number of applications submitted later in 2020. It's a cycle and when the cycle gets disrupted, the effects are not immediate, but are seen over the course of a few months. Also, personal factors are a reason where many applicants may have just deferred immigration due to the uncertainty. Once the 2020 annual report is tabled by IRCC, there will be more details in numbers and charts to evaluate and will give a much better picture.
2. IRCC is trying their best to catch up as the Canadian economy is dependent on immigration. Also, if you see read the transcripts of Parliamentary Committee meeting on the Immigration and Citizenship, where they discussed the impact of COVID, you will see that additional resources have been allocated to IRCC and changes have bene made. So it is a good sign of IRCC adapting.
https://www.ourcommons.ca/Committees/en/CIMM