Google, like always, makes wise choices: When Gmail was first launched, the desire was to have an E-Mail Address on the platform only on invitation.
Afterwards, you needed a Gmail account to use the device when Android-powered smartphones got into the market.
e.g., Yahoo or Hotmail (even your old “main” email is…
Third, Google’s spam filtering and other messages cannot compete with another service.
Fourth: a service has been established by Gmail. GSuite is devoted to corporate owners, so that companies can use Gmail for marketing purposes.