3G technologies used CDMA while LTE uses OFDM so it is a different way of encoding. However, wireless carriers in the US have often increased their number of cell sites substantially - possibly doubling. The amount of spectrum that carriers have has increased substantially - again, more than doubling in some cases. Plus, with the rise of data, consumers now have a way of testing the quality of their link (ie. a speed test) so it's easier to verify under-performing phones. That probably has an impact on device manufacturers. LTE's decreased latency can also make it seem more reliable. Slow ping times mean that downloading a web page can become tedious and seem like it's not working as a script blocks and you're waiting on a 400ms round-trip between the 3G network and getting to the server. Even things like the rise of cheap CDNs like CloudFlare mean that more content is located near you.

5G NR is still OFDM based.