Why is McDonald’s or any fast food always cold now?

I swear every time I order McDonald’s it’s hot when it’s in the bag but cold the within a minute of taking it out of the bag. I remember when fast food stayed hot for a while back years ago. So what gives? Did they do something to the food? Is it poisoned? Are they just doing it in purpose for no apparent reason? I used to enjoy a good cheeseburger but now days you have to make it yourself or go to a restaurant. What are your theories as to why fast food gets colder than homemade or restaurant food now days?