Hash Power – Can Halving Bitcoin Be Delayed?

Currently, the next halving date is May 2020 (tentative) as per the link description here.

I understand that each block of 210,000 blocks is divided by two and that comes down to about once every 4 years.

I guess I have two questions:
1) The 2012 division took place approx. 3.8 years after the genesis, and the halving in 2016 took place 3.6 years later. During this period, the hash rate has increased almost continuously and at an exaggerated rate due to the continued development of mining technology, ranging from general solutions to specific solutions (CPU -> GPU / FPGA -> ASIC). So, are these "premature" weight losses due to the positive rate of change in the hashing rate?

2) A halving on May 23, 2020 is equivalent to about 3.9 years from the last halving. It seems to be related to the lowering of the hash rate in 2018, could a hash rate collapse lead to a halving (ie adding the current 210,000 blocks takes more than 4 years)?

Thank you.