Sure. Think of any collective bargaining relationship -- under either the NLRA or the RLA -- where the two parties (employer and union/employees) have an obligation to bargain.
The union says, "Nope. Not gonna agree to ANYthing the employer proposes, unless it meets with my [unreasonable] precondition(s), and I will not budge one inch from my precondition(s). I will simply refuse to agree with anything the other side proposes, indefinitely, and hold up the progress of the company. I will stand here with my arms crossed and my eyes closed and not budge one inch, forever."
Guess what. At some point, an impasse is reached, and the company gets to impose terms. (Yes, it takes a little longer to get to that point under the RLA compared to the NLRA, but the basic principle is the same: a union cannot simply refuse to bargain indefinitely.) Part of those terms will undoubtedly include the Nicolau award because at some point the company will have to implement SOME sort of merged seniority list in order to completely merge operations. The only list they will dare to implement will be the Nicolau award because if anyone points to the company as "unfarily" implementing any sort of list as some sort of anti-union move, what better defense will it have than to point to the list that went all the way to arbitration pursuant to ALPA's merger policy and say, "Hey, we are only implementing the list THE UNION came up with."
It is even worse for the union in the current East pilot situation. There, you have a situation where the employer is not the cause of the East's problems. The East's union (whoever it is by then) can't say, "We're only being unreasonable because THE COMPANY is being unreasonable." It is purely an internal union issue of how two unionized parties will combine a seniority list. The employer has nothing to do with it. That will make it even less likely a court or administrative agency (NMB) will say it is "unfair" for the employer to implement its terms. This is especially so considering, ironically, the company will most likely be proposing and implementing IMPROVEMENTS to the current East / LOA93 contract.
Additionally, the company can point to commitments by East where that East has agreed to negotiate with the company in good faith to obtain a joint contract.
Let me anticipate your next argument: once the employer reaches the point where it has the right to impose terms, the union has the right to strike. Very true (outside of bankruptcy, as you mentioned). Here, though, ironically and as discussed above, the terms the company will be imposing will likely be BETTER than what East is currently working under. The question will then be, How many East pilots will be willing to strike if the company implements BETTER terms than what they already work under?
The East is truly delusional if it thinks it can hold up the operational merger and the implementation of the Nicolau list indefinitely under these facts.
The JNC met with company yesterday, don't think the union is holding up anything. Do believe everyone will get a vote though. Will ALPA make us vote yes?