I have to agree. It will take some time before there is meaningful feed back on the 2018 MBA's keyboard reliability. Nevertheless, I appreciate the OP starting the thread. We can watch it over time and see how things develop. Clearly, the 2018 MBP has had some problems with the gen 3 keyboard, and there is a lengthy thread on MR with folks sharing their problems with the gen 3 keyboard.
One thing to be aware of: At this time, the 2018 MBP & MBA are not covered by the 4 year keyboard repair/replacement program. So, perhaps Apple thinks they solved the problem, but if you scan the gen 3 keyboard thread, then it seems a bit premature to celebrate.
One question for anyone in the know: the 2018 MBA has a lower power chip, so I am wondering if it runs cooler? If so, could the MBA be less suseptible to keyboard problems aggravated by thermal conditions? I noticed in other threads that some folks seemed to notice the keyboard problems when the machine was under load. Just wondering if anyone has any insight?