1. why ethereum?
it is centralized, buggy, and is not even supposed to be a currency as the developer himself has said.
+ it is a pump and dump altcoin
+ it is heavily manipulated
+ coin distribution has never been fair.
+ it had an ICO which mainly acted as its premine, so we can safely say it is a premined coin!
2. what is stopping people from doing the same with ethereum?
the blockchain size of ethereum is already bigger than bitcoin blockchain and even if the block size is not an issue the blockchain size will be.
3. who said these transactions are spam?
not saying they are or aren't but these are transactions that anybody can make. (there is a problem with this particular address that makes it spam but i want to hear your answer first)
Fundamental analysis suggests that the Etherium will be more capitalized soon. Bitcoin lacks speed and economy at this moment