A bit obscure but does anyone know what prompted changes in MetLife/Hostplus insurance pre-existing condition clause in December 2000?

This is a bit obscure but I'm hoping someone has some relevant knowledge and can help! In 2015, the TPD policy for MetLife insurance in Hostplus had a preexisting condition clause that signiticantly limited benefits for personal super members of the fund.

On 1 December 2020, MetLife and Hostplus entered into a new agreement which deleted all existing clauses and replaced them with new ones which did not include a PEC clause but instead introduced a regime of restricted cover for two years that then became full cover.

I can think of a number of reasons that they might have done this but does anyone know for sure? Or does anyone have an educated guess and what's that guess based on?

Thanks for any help you can provide!