So only saints are in Heaven?
We can be sure that canonized saints are in heaven, but we hope that many others are even though noit formally recognized as saints. A saint is one whose life record and miracles prove to be in heaven and whose life is an example for others to emulate. Someone who has led a mundane but righteous, faith-inspired life would be in heaven but as he is not likely to be an example for others, hje is not likely to be condsidered for canonization. Again, canonization is not a celestial phone book, -- it does not pretend to enumerate the denizens of heaven.
The early church would only canonize martyrs.