I think it depends how hard you work with the plugin.
Sure, and by the time you have a decent result, and found the correct amp setting, etc.etc. you could have recorded the track at better quality (even using just a direct input and a virtual amp) with a real guitarist. I think there would even be time for the guitarist to drive through Los Angeles traffic, spend 5-10 minutes recording the strums, and then go for lunch afterwards and go home, in the time it takes to do the same thing with a plugin.
Also, I'm pretty good and fast at using virtual instrument technology, if I thought there was something good out there, I'd use it all the time like I do with other libraries. I agree that with all plugins that it takes time to get a good result from them, but in this case, the use of time is not efficient - both in terms of labour AND cost. Guitarists are not expensive to hire. On the other hand, let's take Spitfire Audio Albion or ProjectSAM Symphobia. These sample libraries are good, but take effort to make them sounding great. It's worth the time, because to find 60 players in an orchestra AND pay for it (and prepare the sheet music, engineer, venue, etc...), would be horribly inefficient.The performance would of course be more realistic, but also impossible and too expensive to do every time.
With guitar, the case is different, I don't think there is a strumming library that is more cost/time efficient than hiring a real guitarist.
And you're not the only person who has friends that are excellent guitar players. I never said Electricity was bad, I just said it was decent. Most pro guitarists I know think that the plugins sound fake. What they think though doesn't matter, because usually our clients can't tell the difference - but that's not really the discussion here.
It's simple physics at the end of the day. There are SO MANY ways to strum a guitar that it simply cannot be simulated efficiently by any sample libraries. Now, if you're doing simple riffs or power chords, that is different, but we are talking about strumming. Even 8Dio's Songwriting Guitar (which is pre-recorded strum loops) sounds stupid after a while because it is the exact same loops being triggered. There is no variation. The strum loops are convincing, but it's meaningless because the same strums occur. It's the same with these sample libraries.
It's for this same reason that sampled violin is so hard to do. When the violin bow hits the string, a computer cannot accurately simulate the MILLIONS of different ways the horsehair from the violin bow attacks the string. So it never truly sounds like a violin. When you're dealing with wind instruments or percussion instruments, there is a far more limited scope in how each instrument sounds, so they are 'easier' to sample and sound more convincing.
If you were to actually sample it (violin/guitar strums) properly and take into account all of the variations, you would have a sample library of TERABYTES in size. Add in the scripting, and you have a computer killer.
Additionally, when dealing with electric guitar it's a little bit easier because you can use the amp sounds to cover up the bad strumming, but with acoustic guitar...no way...impossible. MusicLab's guitar plugin is pretty good for acoustic, but it still sounds kinda lame after more than 20 seconds of listening. You can get away with it for short periods of time, but as soon as you introduce some repetition (and strumming is ALL about repetition) - it sounds cheesy and fake.
Ultimately, I stand by my original opinion, I may spend more on hiring a guitarist each time I want strums, but honestly, I save myself a bunch of extra work, time, hassle, stress, etc.... I don't think there is a quick way to make good, convincing strumming. And that's what the original post of this thread was about.