Bitcoin2 has been extremely under-valued at the moment.
Give it time, give the Bitcoin 2 Team more time, then we all can witness a magic.
Well, it makes a lot of sense actually that if a lot of people don't yet know about Bitcoin 2, then less people will have claimed them from the fork. Also most of the private keys are owned by exchanges which makes claiming difficult or impossible for most people. So most of the BTC2 will likely remain unclaimed even if millions knew about BTC2 and so the current supply number will never be all that close to the truly circulating supply.
Also hodling BTC2 pays, so that's what most do with their BTC2 right now.
Only major exchanges that currently don't yet list Bitcoin 2, such as Bitfinex would have a lot. Assuming that they even knew which Bitcoin keys on their exchange have a BTC2 balance or bothered and dared to import them. They would essentially use their customers' funds to do so. Which would not go unnoticed for long and would end up outraging their customers who would rather redeem them themselves.
As far as I know, this hasn't really been a problem for any Bitcoin forks but if it ever becomes a problem for Bitcoin 2, there are solutions for such. For example in such a case we could consider locking any unclaimed BTC2 from the fork, thus lowering the supply. (By checking whether or not they have been moved in some way since the earliest blocks of Bitcoin 2. Such as by staking them or by transferring them.) We can already start discussing how you guys would feel about such a move if one day it would be wanted by the community as it is not the kind of decision that the developers should do on their own. The easiest way is to lock them by code from using the BTC2 that they have, based on the public addresses. Such a lock could technically be undone later but if we decide to do it in the first place, it is very unlikely that we would want to undo it.