It just seems to me that the potential downside of throwing away all the good will that has been accumulated by MLB with the MLBPA in recent years by taking a confrontation "big hammer" approach (i.e. lockout) far outweighs the potential benefit of what they would gain, especially when it's possible (maybe not likely, but certainly can be used as a bargaining chip) that the "void contracts for PED use" could be mutually agreed upon in the next CBA.
I just don't see it happening.