I don't think it works like that. If Spiderman sells extremely well that will up the value of Insomniac and will make it even harder for Sony to buy them. Its never the best time to buy a studio when a studio is doing well, and when Insomniac is doing extremely well, they wont see the point in being brought.  Some cases may occur like Playground Games for Xbox, however Horizon series isn't known for selling well and making huge profits, instead the series is known for its great reviews, plus MS have a butt load of cash where as Sony isn't in the same league as them when it comes to the bank. I wouldn't be surprise if Sony picks them up eventually but buying them at there peak wouldn't be a cheap move. 

Are you crazy ?  Sony can buy Insomniac without even blinking, your comparing a game developer to a massive corporation.  Serious though, they could use the spare change of Sony to purchase Insomniac

Sony can drop a couple hundred millions no problem on anything. tho insomniac is worth nowhere as much as that

Inso is worth 100 million at most. tho I have no idea how am calculating this . just a guess. I'd say 50 million

Well I think it may be in the range of 50-100 million just because I don't know what assets they hold, could be worth much more if they own their own office etc etc. But I think they are worth the investment, they are a super polished developer with Sony who has been around forever and besides a couple one offs have always worked with Sony. Sony isn't afraid to invest alot of money if they feel the investment will pay off and increase their marketshare

also the risk of getting an offer out of nowhere from MS which is much bigger than Sony is worrisome. 

also. Insomniac is more important to Sony than most of their first party studios. except ND and SSM and GG.

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 

according to the titles they put out that were far more successful than anything Bend,Japan,London,MM,SPP,San Diego   put out. or the other ones besides the first three I mentioned 

am using the long lasting and sales of ips they made for Sony

My feeling is Insomniac deciding to go with anybody would come down to either their financial position or Ted Price retiring rather than any kind of feeling , on Sony's side they have to be mindful of past industry  acquisitions where the top creative people leave before any type of legacy can be created,this goes double for studios with the same leadership since inception  at least with someone like say bioware you have gained their portfolio,unlike Insomniac who's portfolio is made up in the majority by Sony IP.