There's room for argument about some of the details. For example, I've omitted some of the rarely-used standards such as the original 802.11 and 802.11a, as well as some of the early 100 GBps Ethernet standards, in attempt at getting at least some approximation of speeds that were used fairly widely, not things that ended up as little more than technology demos. Depending on what you decided to include, you could get a somewhat different graph from this.

With that proviso, I get a graph of relative speeds something like this:

[![enter image description here][1]][1]

That looks to me like since the introduction of 802.11b, the two have been tracking *fairly* closely in terms of speed growth. Even though this is on a logarithmic scale, it looks like Ethernet (ignoring the pre-1995 period) has marginally faster growth, but given the small number of data points, I don't think either has a really massive advantage (note, that is to say: Ethernet has a speed advantage at all times, but its speed advantage has remained approximately constant for quite a while).

It's also worth noting that as speeds have gone up, distance has gone down (for both technologies). The newest/fastest 802.11 (802.11ad) operates at high enough frequency that its target range is "at least a meter", and generally won't go through walls at all. At least to me, that seems to leave some room for question whether we're likely to see it continue growing a whole lot. If I were being entirely fair about things, I'd probably have left it off the chart entirely--actual use seems to be extremely limited, at best. Even if I included it, I probably should have cut the speed in half (or so). What I've shown is the 8 Gbps variant, but most of the wireless routers I've seen only do the 4 Gbps variant (though most can also do an 802.11ac and 802.11n stream at the same time, so they're around 5.5-6 Gbps total).

One other note: this is all based on theoretical maximum speed supported by a given standard. In terms of real speed, it seems (at least to me) that 802.11 is typically slower by an even larger factor than the theoretical maximum implies. With Ethernet you can routinely expect to use 80% of theoretical bandwidth, but with 802.11 you're lucky to use 50% of theoretical (and often substantially less than that).

  [1]: https://i.sstatic.net/uxKaM.png