both sides are in many ways right in their criticisms about the other side, they are just fundamentally conflicting visions of the long term nature of the network.
In my opinion the problem here is the network was built so that it operated only by people acting on incentives and those incentives being aligned with the good of the network, and it turned out that miners acting in their own interest wasn't actually good for scaling past a certain size and operating on certain types of transactions.
You should ask the question about Core developers' incentives: what do they personally gain from scaling bitcoin? Nothing, at best increase in value of their holdings which they share with lots of free-riders, and only until they sell. They only gain continuously if scaling is prevented as that opens space for their second-layer solutions - presumably to be enabled by planned 'improvements' to bitcoin. Ie. their only incentive is to capture bitcoin for rent extraction.
Miners are the only entities that have a continued incentive to improve bitcoin directly.
In my opinion the problem here is the network was built so that it operated only by people acting on incentives and those incentives being aligned with the good of the network, and it turned out that miners acting in their own interest wasn't actually good for scaling past a certain size and operating on certain types of transactions.