In bitcoin technology, there no way do identify which spam or not.
It just because transaction volume already reach the limit, bigger than bitcoin can handle....sad but i have to admit it. Average daily transaction already reach the limit. No space anymore for new adopters or bigger transactions volume.
Of course not. A transaction is a transaction. But we all know what's going to clog and what won't as do the people sending them. Many wallets won't let you choose fees that low and with others you have to actively create them. They know what they're doing.
When this isn't happening there is still more than enough capacity. In August the mempool was empty and zero fee transactions often got through. With Bitcoin without second layers there will always be a limit and people will always attack BTC by exploiting it. 2-3-4MB blocks won't make much difference.
So it will be problem and problem....and trust gone. Remember, bitcoin value only about trust and faith. If this keep happening, people wont use it anymore and decrease value.
Not everybody use bitcoin with huge transactions. Often they use to send 300-1500$, which it doesn't make sense to spent 15-50$ on transactions fee. And they have to wait few hours or days to get their transactions confirmed...
Except there no alternative.