But each family member will have their own seed phrase. When generating a new seed phrase, of course, you can create millions of BTC-wallets, but this creates a problem due to the increase in the number of seed phrases (all this needs to be saved).
The point is to be able to create the maximum number of addresses with one seed phrase.
If you haven't read it, I recommend visiting my thread about
BIP-85, a smart way to unify backups by storing multiple mnemonics derived from a single seed (master) that solves this problem.
Of course, there are different types of btc that can be used, which will increase the limit of available addresses. But, for example, in signature campaigns, the segwit type is used and with frequent changes of campaigns, for example, this limit will be quickly exhausted.
If we also take into account the undesirability of reusing the same address, then the limit in BTC-addresses will still be quickly exhausted.
What are you concerned about? Are you referring to the "limit" of addresses that Trezor Suite can reach - gap_limit or are you actually concerned about the end of addresses generated by an extended key?