I suppose you could use supermarket food essences. The problem is that some of these are oil-based afaik. Avoiding coronavirus but dying from EVALI would be ironic.
I think it's unlikely that DIYers will run out of flavours. In my experience, one runs out of nic, VG and PG long before running out of flavours. Sure, you might run out of the flavour that is needed to make your favourite recipe, but you won't run out of flavours. You will have some flavour to add to a mix. There is no DIYer who will run out of Flv Rich Cinnamon ever. The bottle you bought in 2018 will be handed down from generation to generation as an heirloom. Your great-grandchildren will still be using it.
I think it's unlikely that DIYers will run out of flavours. In my experience, one runs out of nic, VG and PG long before running out of flavours. Sure, you might run out of the flavour that is needed to make your favourite recipe, but you won't run out of flavours. You will have some flavour to add to a mix. There is no DIYer who will run out of Flv Rich Cinnamon ever. The bottle you bought in 2018 will be handed down from generation to generation as an heirloom. Your great-grandchildren will still be using it.