Here's why:
Because Dolphin fans are always hyped on their squad in the summer. I've heard we're gonna be a 10+ win team every year for the past... every single year I've been on this board. The year we went 1-15 people were saying 9-7 haha.
Because everyone overrates the team in the spring. Part of it is because some players are good at practice but not when the pads come on they suck. Or they only look good in practice because they’re practicing against other scrubs.
That leads to fans thinking Miami can be a 10 win team based on a bunch of ifs:
If Tannehill takes the next step
If the O-line plays above average consistently
If Drake plays like he did last 5 games last season
If Parker becomes an alpha WR
If Mcmillian becomes a stud LB
If Jordan Philips has a breakthrough
If Harris plays like his draft status
If tank steps up to be the #2 corner
If injuries are few
If Gesicki becomes a red zone threat.
If branch earns his contract
If wake avoids Father Time
All that is highly unrealistic individually let alone all of that becoming true in one season at the same time. That never happens for any team ever.