I think also that the article is more an "expression of wishes" of a Bitcoin hodler & maximalist, but I considered it interesting for discussion. Mostly the article doesn't take into account that speculation is actually the most important use case for altcoins.
But I think drivechains could have an impact on some altcoins whose "unique selling proposition" is tied to a certain feature that is replicable on a Bitcoin sidechain. That's why RSK, once it is totally decentralized, could "steal" some serious market share on the "smart contract market" from Ethereum.
Other altcoins, like those that use "energy-efficient" consensus methods like Proof of Stake or Proof of Burn - if they prove to be long-term viable - would not be that much affected, as the Bitcoin main chain still would use the energy-consuming Proof of Work. Other altcoins that wouldn't be affected are those that provide on-chain scalability with innovative methods like
Child Chains or DAGs. "On-chain" transactions very probably would be considered superior than "sidechain" transactions, so these coins would have an advantage over Bitcoin and could use that for speculation.
Overall, drivechains are an extreme interesting technology - and I think if they work as expected, they will be a nice "second layer" between the mainchain and LN/off-chain methods.