Sending spam that actually takes up space in the blockchain requires that the spam pay transaction fees just like everybody else.  Perhaps the spammers just ran out of funds?  Or perhaps the fees got so expensive that the spammers decided it wasn't worth the cost anymore?

For all I know there are actually coins which solve most of these problems, but the problem is that pretty dodgy or weak coins tend to be the best at getting pumped and the owners best at profiteering, especially with coins like DASH which have a large instamine but can appeal to newbies who know less about that.

Monero has no block limits.  Yes, the transactions are bigger in bytes ( I think 3 or 4 times bigger), but there's no hard limit. Blocks adapt.  Only limited by network capacity and disk size, so following Moore's law.

funny thing is, both sides believe that if their coin wins, there will be a price boom.
-snip-