Yeah it's definitely headed that way. I just don't think we'll ever see an elimination of the starter and the emergence of a team that throws primarily bullpen games, unless the roster rules change dramatically.
Teams can't continue to move players up and down for a long stretch or their players will start running out of options.
I also thought that as an obstacle, but it was due to my misunderstanding "player options".
Yes, after using three Options for a player the team must expose him to the waiver wire.
But an Option does not = being sent to minors.
A single move from 25man (majors) to minors (40man) in April, for example -- triggers One Option.
And then for remainder of that season, the club can move him back and forth as frequently as they wish provided the player remains in minors for minimum of ten days.
If a club chooses to demote a player from 25man to minors in three of their first five seasons of MLB service, they are now out of Options for that player in next two seasons. (Rules change a bit after 5 MLB seasons).
The limit of 3 Options per player extends across MLB teams in event of their being traded and/or FA signed to another club. Thus some young players may join a team with only two or one Options remaining available.
Meanwhile a player who has never been sent to minors from a 25man roster (for example, Evan Longoria) still has all three Options available were the Giants or any future team wanting to toggle him up and down to AAA
See:
https://www.mlbdailydish.com/platform/amp/2011/9/3/2400914/mlb-roster-rules-25-man-roster
and again note that I myself could not have accurately explained this before reading above article