It isn't just the shift though.
Baseball has found that the best way to prevent runs is the strike out. Pitchers are throwing harder and harder every year and facing hitters less which makes hitting more difficult.
Offenses have realized that the likely aren't stringing together 4 hits against mid-90's fastball and 90 mph sliders, so launch angle was born. HR are the best way to score against modern pitchers and looking for your pitch to crush.
All of this plus shifts has led to the modern 3 outcome and less action in the games. How do you change it though? Lowering the mound might help, but that just might spike HRs. Playing around with the ball? I have no clue.
Lower ticket and concession prices has helped attendance numbers - try that
I think making tanking less appealing at building teams would help. The desire to pay amateurs less has led to tanking to being the way to build teams. The worst place to be is a competitive, but not elite team. Better teams, more exciting games. Less blow outs will help.