The reason is pretty simple: the adoption hasn't grown enough for the current block capacity to not-be enough for the legitimate usage.
And how do you measure that? Even if we were to follow that route, and have a block size limit that corresponds to the "legitimate usage", how do we begin? In my opinion, the adoption has grown a lot since the last time the Bitcoin community had had this debate.
ETH was pushing over 1 MB blocks every 30 seconds and if we look at the times it was POW the hashrate and the nodes were far more decentralized than BTC, so no, the whole thing holds no water. Dogecoin does so over 60 seconds, only for BTC would those pose problems, because...no reason!
When Ethereum supported Proof-of-Work, it had so called "uncle blocks" (the respective stale blocks in Bitcoin), but that came with additional economic complexity (I wouldn't suggest comparing Bitcoin with Ethereum as they are different in almost everything). As for Dogecoin, lol. If you believe anyone takes this seriously, then I don't know what to say.