Is it normal for players to ghost out of a campaign?

Is it fairly normal to have players silently drop out of a game instead of being "hey this just isn't my thing, but thanks for trying"? Even if said players are close friends? This is the first group I've DM'd for and I just found out the married couple that ghosted me is playing with another group - which I was 99% certain was happening - but seeing it confirmed is making it hard to not take personally right now.

Losing two players killed the group, for the record. We started small since it was my first time DM'ing. The one player that was really into the game is wanting to restart it. My neighbor wants to join too, after reading the world material, but we're not sure who to recruit for our third player yet.