It's not the first project that I have seen that was cancelled. Building a PSS (RES and/or INV) is not a small thing, given that there is so much complexity in the airline industry which has to be supported. I think it would be very exciting if Google continued these developments. Some of the major players (e.g. 1A) are in a quasi-monopoly and they definitely exploit that. More competition would be good. (But I agree, I don't see why Google would want to compete.)

Btw, many of the PSS vendors already have or are currently in the process of renewing their "expensive mainframes with ugly old code bases".