It's caused by he was an agenda for doge coin. Remember that elon was mentioning on his tweet if he needs a crypto that can be used in mars and doge coin is including on his project.
he was also buying lots of doge coins and you must see that there are some addresses that owned more than 50% of total supply.
Elon will not buy something if that will not be really useful for him. The communities have been talking about this since at the end of last year.
I don't think Dogecoin is the only coin that he can used on Mars. Nothing special from Dogecoin but it is attractive because Elon can be a biggest influential person for this coin. He is wise and takes this opportunity. Accumulation 2 or 3 years ago and choose a bull market and altcoin season to shill it to the Moon.
The adoption of SpaceX for DOGE-1 is only official announcement that he is a supporter of Dogecoin.
Many other altcoins can be used as same as Dogecoin but this coin has big network hashrates that many other shit altcoins don't have. It is another characteristic that makes Dogecoin is different among the crowd of altcoins.