They can command big bonuses but they still fail at an incredibly high rate - much much higher than the Rule 4 draft, even on the high school pick side
Just go look at the top bonuses from basically any year.
2016:
Kevin Maitan, 4.25M
Luis Almanzar, 4M
Lazarito Armenteros, 3M
Alfredo Rodriguez, 7M
Yasel Antuna, 3.9M
Abraham Gutierrez, 3.5M
2019
Robert Puason, 5.1M
Bayron Lora, 4.2M
Erick Pena, 3.8M
2022
Yoelqui Céspedes, OF, Cuba – White Sox ($2,050,000) # More »
Oscar Colas, LHP/OF, Cuba -- TBD
Wilman Diaz, SS, Venezuela – Dodgers ($2,697,500) # More »
Carlos Colmenarez, SS, Venezuela – Rays ($3,000,000) # More »
Armando Cruz, SS, Dominican Republic – Nationals ($3,900,000) # More »
Cristian Hernandez, SS, Dominican Republic – Cubs ($3,000,000) More »
Pedro Leon, OF, Cuba – Astros ($4,000,000) # More »
Jesus Galiz, C, Venezuela – Dodgers ($812,500) # More »
Rickardo Perez, C, Venezuela – Phillies ($1,000,000) More »
Yiddi Cappe, SS, Cuba – Marlins ($3,500,000) # More »
Go look up any given year. The league collectively goes like 3/30 on players that get $1M or more and maybe 2/10 on guys who get $2M or more. Possibly not even a success rate that high.
So it's not some travesty that Bonnilla sucks or some big whiff. I mean yeah it's a whiff but he had a 90% chance of never making it anyway.