I think it's pretty unlikely we will see very small carriers like what you describe because of the large fixed costs with operating carriers. A carrier carrying 6 aircraft would still be very expensive and require a lot of highly trained personnel to operate. Certainly on a per aircraft basis it would be several times more expensive to operate than a more typical carrier like those in service today. You can't simply say, "Well this carrier operates 1/6 the aircraft of the other carrier so it costs 1/6." This is to say nothing of how only having 6 aircraft would effectively prevent you from fielding special mission planes like EW and AEW aircraft. Would it be more expendable? Sure, a little, but it would still be quite expensive, I'm skeptical that it would be expendable enough.
It's difficult to say how vulnerable carriers really are. There's a lot of theoretical projections but until we actually have a hot war nobody really knows for sure how those theories translate into reality. Maybe carriers are actually very difficult to hit because the kill chain doesn't work as well in an actual hot war than in theory. Maybe carriers are sitting ducks and DF-21 sinks every last USN carrier before they so much as launch a plane. Nobody really knows but given that both USN and PLAN are building carriers it seems the consensus is that they're not useless sitting ducks. So assuming they are is perhaps a bit hasty.
Of course sometimes the military planners are wrong and things develop differently from expectations. Let's say that carriers really are extremely vulnerable. What then? Well most likely the answer would be to simply not have carriers, not build smaller more expendable carriers. After WW2 heavy battleships with thick armor went away, they weren't really replaced with smaller versions of themselves. What if air power turns out to be very important and you absolutely must have it? Even in that scenario I don't envision very small carriers being built, rather what will most likely happen is the defender will simply have an overwhelming advantage and attacks across long distances without nearby land bases just becomes impossible. At the end of the day I just don't think you can make the cost benefit of very small carriers to be worth it.
While battleships were not replaced by smaller versions of themselves, some of the role that they filled during WW2 were replaced by newer ships that filled similar roles. My suggestion is not simply for a smaller version of supercarriers, but something different that can fill some of the role of the carrier which is sustainable air superiority in the open ocean. Other roles such as aerial ISR in the open ocean would not be replicated on such a ship.
Its role is not an air base in the ocean, its role would solely be a moving platform. Its capabilities would be cut down as much as possible compared to a regular carrier so that it can accomplish that one role. It wouldn't just carry less aircrafts, it would cut down on many other things e.g. repairs, radar, and aircraft types. They wouldn't need simultaneous launch and recovery capabilities, they'd carry just one type of aircraft, they'd only be able to do basic maintenance on the aircraft itself, they'd need hangar space for only maybe 1 or 2 aircrafts for maintenance operations. In some ways it's also like the Soviet tank doctrine vs. the Western one, where the crew and the gear has much more limited responsibilities and everything else would need to be done at port whereas Western counterparts can do many of them in the field.
The actual air base in the ocean would then be fulfilled by carriers far larger than today's and would be capable of carrying anything that the air force can carry including the likes of naval equivalents of Y-20 and H-20. They would be far behind the picket fence of smaller, more expendable platforms but also providing them with the ISR, EW, refueling, long range strike, etc. needs.
