This one is very common from the Bitcoin cult, and is techically true.
However, there is a lot of thought and intentional design that has gone into the supply dynamics of Monero. Monero implements a “defined supply” of 18.4m coins, and has a tail emission of 0.6XMR per block after the defined supply has been mined. That tail emission starts ~May, 2022.
This means that Monero has extremely low inflation that approaches 0% forever, and is technically “disinflationary” or “asymptotatically approaching 0% inflation”. The inflation rate is currently lower than Bitcoin and gold, and will continue to decrease. It’s also important to realize that a low inflation rate like that of Monero is a way to replace lost coins over time in circulation, but is likely even too little inflation to account for lost coins (rough estimates are ~1.5% of coins lost in circulation each year, compared to Monero’s current inflation rate of 1.12% as of writing). This would mean that Monero is in fact deflationary, even with the low perpetual issuance.
It’s also extremely important to make it clear that Monero’s supply is pre-defined, verified and enforced via consensus, and entirely predictable, just like Bitcoin’s – you can know the inflation rate and totaly supply at any point in the future without doubts.
This tail emission enables two key features in Monero
A lower bound of network security forever (miners will always be able to rely on 0.6XMR per block, no matter the fee market)
A dynamic block size (Monero’s blocks can grow/shrink to adapt to short-term increases in usage, with a penalty to mining rewards during these times).
For more on both of these, see the resources below.
Resources
Descriptive website with graphs showing the supply dynamics of Monero: https://monero.supply
“Why Monero has a tail emission”: https://localmonero.co/knowledge/monero-tail-emission
“How Monero Solved the Block Size Problem That Plagues Bitcoin”: https://localmonero.co/knowledge/dynamic-block-size
Inherent risks in not having a defined block reward in perpetuity: https://www.cs.princeton.edu/~arvindn/publications/mining_CCS.pdf