If Gods Will is to Heal, Why not all Healed?

First answer this question

If Gods Will is that all to be Saved, Why not all Saved?

2 Peter 3:9
New King James Version (NKJV)

⁹ The Lord is not slack concerning His promise, as some count slackness, but is long suffering toward us, not willing that any should perish but that all should come to repentance.