Increasingly less so. 2G to 3G was a very clear cut on the radio side (TDMA to CDMA); 4G changed both the radio side (OFDMA) and the core (no more circuit switching, more Internet-standards-like).

5G is already much less clear: 5G non-SA literally depends on 4G for signaling and uses 5G-NR (which itself is still OFDMA) only for user data. 5G SA changes the core network again, but isn’t even supported in many networks worldwide.

There are huge jumps in bandwidth within a generation too. 3G started out with circuit-switched-ish 384 kbit/s and ended with 40+ Mbit/s on HSPA+. The jump from that to early LTE was much smaller in comparison.

So in a way, the model of “every once in a while, the carriers and manufacturers bundle up a bunch of optional extensions and call it (n+1)” seems to be coming for 3GPP just like it already has for e.g. 802.11.

Tell that to the cellular industry marketing people who decided to put "4.5G" on things. Also not everything that is marketed "5G" is equal in capability, there's a myriad of different bands in different regulatory regimes in the world, some of which go through material like brick/concrete much better than others. You'll see "5G" connections that have speed tests in an urban area that top out at 50 Mbps downstream and others where you'll have 850 Mbps.

https://en.wikipedia.org/wiki/LTE_frequency_bands

Even within a category such as "4G" there have been significant advances in some radio capabilities since it was introduced, like MU-MIMO, vs early "4G".

There's a very large number of different things that are all being marketed as "5G" now, so it's really a drastic oversimplification to try to say that all 5G is the same thing. Do you not remember the very early days of "3G" when cellular carriers were trying to market EDGE/GPRS as if it was 3G?

The "G" marketing gets especially confused in the US where carriers branded EDGE as "3G" and HSPA+ as "4G"