Multifilament definitely has a place in the overall tennis universe, but on tour where cost isn’t much of a concern, it’s hard for any multi to stand out versus natural gut on the one hand and poly on the other. I tend to agree that multi is not competitive as a main string, because natural gut (even a cheaper one) will have noticeably more comfort, feel and durability than a multi. And you can always cross natural gut with a poly to reduce power / increase the spin potential of the string setup.
Where I think multi has an opportunity is as a full bed setup. The string manufacturers can create a multi that has hybrid characteristics (e.g., a multifilament/gutlike core with a durable outer layer with poly characteristics). In fact, the string companies have already done this but I don’t think they’ve marketed these products the right way. Most people still look to an actual hybrid setup to get the best of both worlds. Not that many people will look to a string that was designed to have both qualities, for whatever reason. For me, I’ve played with Head Velocity which I felt was quite good in terms of feel, touch, power but it also had this thick outer layer that allowed the strings to slide to achieve the proverbial “snap back” for spin and at ~$10 a pack it’s a great “multi”, even though in my opinion it is quite different from traditional multi‘s such as NXT, NRG, X1, etc. bc it has some poly characteristics.
I do think NXT, NRG, X1, etc. having a place as a cross string that is strung with poly mains, as it wouldn’t make sense, even at the pro level, to use expensive natural gut as a cross string. It is the main string that contributes 80% of the feel/performance of the stringbed.
