I think it was because IOTA experienced an influx of spam transactions which were not dealt with properly. I'm sure that IOTA still has issues but I think that

I think it was because IOTA experienced an influx of spam transactions which were not dealt with properly. I'm sure that IOTA still has issues but I think that the core DAG/tangle concept is sound. Unlike with most other tokens, these problems should be relatively easy to fix... My bet is that it's much easier to scale a DAG than a Blockchain. But I'm sure that some blockchain-based tokens will also scale eventually.