I think you are missing something: IBM owns OS/2 (I will ignore the Microsoft parts). If you include any part of the existing OS/2, in a new distribution, you need a license to do that (Serenity Sytems, or Mensys, has that license today, and I expect that IBM would not allow them to sell it, or even give it away).
Okay, you propose to replace all parts that are still copyright by IBM. The only problem with that, is that you are looking at roughly 100 man years of development to get it all done, and tested. Even if it takes half that time, and you can find 10 developers who are willing to do it, for free, that is 5 years (working around the clock) before anything, except the odd update to the current eCS, for those who already have a license, can be released. 5 years, with no new users (remember that you can only include the stuff that is not part of OS/2), and a loss of those who just can't wait that long, will mean that the user base will be insufficient to support such an effort. Then, there is the question about how long the current PC will exist. I expect that personal devices (tablets, phones, and wrist computers) will replace what we know today, in the near future (5 years). We would also lose a great number of commercial customers, who can't afford to be caught using unlicensed (or even questionable) software. Some of them also require it to pass reliability tests, and other things, so they would be scrambling to find an alternative. They are probably pushing the envelope already, and they likely would not come back.
It is suggested that "Abandon ware" will cover it. I am no lawyer, but I expect that there is a waiting period (starting when Mensys abandons it, and IBM refuses to issue a new license), before it can be considered to be abandoned.
Time is the main enemy, followed closely by the lack of manpower to do the job.
I don't know why people think that if it is not a company behind OS/2-eCS we are doom.
You have obviously never dealt with IBM. They never really embraced the open source concept, and they are not likely to pay lawyers to clear the way for what you propose. In fact, I am not so sure that they ever got over "the IBM PC is just a toy" concept. If it doesn't make a dollar, they just won't do it. That probably also means that they won't chase an individual, as long as they don't get too carried away, but including copies of an IBM copyright product, with some other package, without paying royalties, forces them to take legal action. If they don't, that would open the doors for anybody to use any of their copyright material, for whatever purpose they like. IBM just can't afford to let that happen.
So, the other option, is to let the user obtain an appropriate version of OS/2, on the open market, then package eCS (I will call it that) as an add on, that does not include the base OS (and that will be completely useless, on it's own). One of the problems could be the availability of fix packs etc. Of course, as the base OS gets replaced, more of it can be included in the new package. After all (or most) parts of the existing OS/2 get replaced, the package will be complete, and the user will no longer need a copy of OS/2 to supply parts that have not been replaced. See my previous time, and manpower, estimates - which are likely on the low side. Meanwhile, time marches on, eCS has gained very little ground, and has probably lost a lot of users, simply because they can't wait for results.
I suggest that we wait, for a while, to see what Mensys or XEU, actually does. It is likely that no decisions have been made, yet, and we should get some sort of statement from them, when a decision is made.
I see three possible scenarios:
1) They will just shut down eComStation, and remove it from internet access.
2) They will shut down eComStation, and make the project available to the public (that may depend on what the contract with IBM says).
3) They will continue as it has been.
If 1), we will need to start over from the beginning.
If 2), somebody will need to pick it up, and run with it. No small feat, and there would be a learning curve to deal with.
If 3), we still have the same problems that we have today.
So, it won't hurt to try replacing parts of OS/2. Some have already been done, but finding someone who would even consider doing the job has proven to be difficult, and a lot of them would want to keep their work closed source. I don't see that starting with the WPS would be a good idea. It is too big, although XWorkplace is a probably a good start. Parts like the TCP stack would make more sense, but that is pretty specialized. CMD.EXE has a replacement in 4OS2, but there are incompatibilities that need to be addressed (perhaps that would be a good place to start though). There are a lot of drivers that could be tackled, but we desperately need new drivers for new devices, and that is proving to be more work than expected, so old device drivers that still work, get ignored. It seems that OS2LDR and OS2KRNL, are under way, and have been for some years, with some success, even with the questions about the legality of the OS4 project.
I guess we need a priority list, that can be picked by those who are willing, and able, to do the job. Some of that has been tried on OS2world, with minor success. Mensys has picked up some of the very important things (ACPI, AHCI, Multimac, Firefox), but there is much more that needs to be done, and soon. Paul Smedley has been looking at Multimac, but there are a few problems to sort out, and he certainly doesn't have the time that is necessary. At the current rate, I figure that 100 man years of work, will take close to 300 years to get it all finished.
Again: Time is the main enemy, followed closely by the lack of manpower to do the job.