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The spam attacks cause everyone to pay more to get their transaction confirmed. If the max block size were increased then the cost of these spam attacks would grow exponentially, and the effectiveness of these transactions to decline.
A mere inconvenience, same as having to wait for a confirmation in order to make sure you can trust the input. Both have a cost, one in time, the other in coins.
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No, its not fixed. We just ignore all transactions. This causes issues for users using old software.
You can say the same thing about every soft fork. However users of non-full-node wallets
should receive notification that their transactions have been rejected, which should hopefully get them to upgrade.
They get messages alright, usually the message gives them no indication what to do though. You can blame that on bad error messages, its still a problem.
Full node users tend to be more active in upgrading, however they can view their transactions (or that their transactions have been rejected) on one of many block explorers, which might get them to upgrade in addition to the warning message to upgrade.
38% are currently running the latest version ->
https://bitnodes.21.co/dashboard/?days=90Old data are not shown (or only as other) so I cant say how long it exactly took until the network had upgraded to the mellability quick fix, but thats all it is. Im not inclined to believe that node operators are not more active in upgrading, unless you can show me data to support that statement.
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I am not sure what you are saying here? I am trying to describe the small number of businesses that are affected by malleability under current node rules.
SegWit is not needed, its not necessary, Bitcoin would still exist and work without it. SegWit however properly fixes a long term problem that keeps coming back and is currently crudely fixed. It also offeres many opportunities for a larger number of different transaction types. The increase in transactions per block doesnt hurt either.