Why are you so adamant that they must be suckers? Don't these kind of purchases happen all the time? Let's say you want at least ....10 years of fat profit worth for you to sell your business. Could be more since it's sustainable, has high margins, etc but let's pick the round number. Big company comes along and offers you 11 years of profit worth of money. You sell. They know it's going to take a bit longer for the purchase to pay for itself but they also want to transform the business a bit to funnel in developers to popularize their main products and take wind out of the sails of competitors which they project will bring in the equivalent of at least 3 years of your business's profit over time along with some other stuff....so they're happy to overpay for your business since it'll probably cover the lil bit of extra risk

In that case everyone's a winner...except maybe us as customers.