Stealth planes are no longer invisible. Stealthyness has to be "tuned" to certain radar frequencies and radar systems can now scan frequencies looking for the aircraft/drones. The advantage they do have is that generally speaking, they are pretty good at hiding from the frequencies needed to target an aircraft with a weapon. If we sent an F-35 into a theater the way the F-117 went into Baghdad, it would be a turkey shoot for the Russians/Chinese.
So is stealth really worth the cost and more importantly the negative impacts on aerodynamics? For now, careful mission planning and really good stealth qualities make F-35's pretty effective. But when you know how stealth works, it's pretty simple to see how to defeat it: multiple radar scanning at multiple frequencies. It's pretty safe to assume no one has this, however, as everyone is putting tons of effort into developing stealth aircraft.