Mojang also was merely a game developer and Microsoft had to pay over 2 billion for them due to the popularity of their game.
the game had almost 100 million units sold. it had tons of licensing to clothing and merchandise and other licensing from other games or on TV. probably brings in hundreds of millions of dollars in revenue every year back then.
it doesn't even compare. Microsoft paid 99% of that money for minecraft not mojang.
insomniac is merely a single player game dev with niche games . they aren't worth more than 100 million. and that might be a high estimate