Well, I don't really see how it can be stress-free because Internet is not always dependable anywhere. Will the SIM card as we know it today cease to exist and instead people will become accustomed to instant virtual numbers as needed over networks of all types, making worldwide travel and stressfree communication the standard?
Virtual number, direct inward dialing and network technology are all different now than they were in say, the late 1990s. I remember when all I could get was CDMA in the US which meant I was situation-normal-all-messed-up from 2002 - 2010 even while traveling for DIDX in Europe, Middle East and Asia. I had to keep the same phone number no matter where I moved unless I used a virtualphoneline and routed it via FreeWorldDialup or something like that.
Even GSM feels like a very old technology and either today or tomorrow it is going...gone. Check out Republic Wireless (republicwireless.com), Google Pixel (https://store.google.com/product/pixel_phone) and Sprint Wifi (https://www.sprint.com/landings/wifi-on-the-go/). They already offer connection via eSim, and it's considered SIM-less. A few hundred DIDX direct inward dialing phone number customers offer such paired with access to virtual numbers as needed according to business and travel needs. It seems like most them have the word "roaming" in their company name.
Still, eSIM use is in the infancy stage, and reviews may not be very good because it is so dependent upon Internet driven connections. Problems with reception and connectivity can make them feel unreliable. It has to improve, and I am sure the best answer to this is in one of these kids' minds who play with Legos, virtual headsets and SnapChat while jumping at the local trampoline park during their free time.
eSim has so many advantages over traditional SIM line. The calls are less expensive, and traveling is not interrupted because changing one's country of residence does not affect call rate! It is geographically-boundary-free phone service because of Internet connectivity. Plus, 3G Wifi is usually free, etc.
Telecoms have to invest big money in infrastructure changes, something they all talk about at TelcoDays Las Vegas, CommunicAsia, ITW and ITEXPO.
With such a large majority of consumers using mobile phones with traditional SIM, our DIDX head developer Kamal Panhwar guesses it will take at least 10 years before eSIM will become more of the norm. It will change definitely to take advantage of WIFI and Internet connectivity, without Sim...but I think it will happen just in time for some newer technology that promises even more efficient and empowering mobile communications in some really unusual way none of us are thinking about right now.