In case you don't have access to a pressure sensitive device....
This is somewhat possible via a blend. But due to how blends behave, in many cases spacing will require manual refinement.
- Create a blend, specified steps
- Replace Spine
- Alter blend options to set blend to be
Relative to pathand then increase steps to space the small end better
- Expand the blend
- Manually remove superfluous objects and then manually reposition a few objects for better spacing
This is far from perfect, but may offer a relative shortcut by supplying overall rotation and sizing to follow the path desired.
If you wish to achieve precision, then there's really nothing "automated" that will accomplish that which I am aware of. You would need to manually determine sizes, positions, and rotation degrees if you want things to be precise.
Assuming I've understood your question properly, it is kind of possible.
Here's one method which involves the use of a graphics tablet and pressure sensitive stylus, such as a Wacom.
Draw a star, and use it to create a Scatter Brush, with settings as shown below. When you use the Brush Tool, press harder at one end and release the pressure gradually as you draw. It might take a couple of attempts to get the pressure right.