The key here isn't for IBM to win, but to slow down the hiring process.
The information these key executives have is time sensitive. If you can get them to delay their hiring by 6 months, then the effort was worth it.
Just FYI... in some of these contracts there are two or more clauses that restricts where you can go to work post IBM... One clause is overly restrictive and worthless. The second clause usually contains one or two companies and is probably enforceable.
As to the lawyers, they are in house counsel so their fees are paid whether they go to court, or sit around in the break room.