There are a few "blockchain networks" which don't charge a fee per transaction. This makes them useful for micropayments, when you really want don't want to break the bank. Many DAGs like NANO and IOTA are feeless by design, so this should make them extremely-practical networks for day-to-day payments. But sometimes I wonder how such cryptocurrencies are able to survive in the long run without an incentive mechanism. After all, the network fees are what attracts miners (or stakers/validators) into helping secure the blockchain against double spend attacks.
Without any incentive, validators would be participating in a voluntary manner. This means, coins without a network fee would be less-secure than those with a network fee. You can see how Bitcoin is the most secure cryptocurrency in the world, even though many criticize its high network fees (although they've lowered recently). A high network fee will attract as much miners/stakers/validators into the Blockchain, effectively keeping it extremely secure against double spend attacks. The end user would benefit a lot from zero fees, but those who support the blockchain itself won't. That's why I believe zero-fee chains will ultimately fail in the long run. Or maybe I'm wrong?
What do you think about this? Will feeless blockchains have a future? If not, why? Your input will be greatly appreciated. Thanks.