The whole point of this discussion is ignoring a very important point: semi-auto rifles a re a weapon used at the Squad-level, while infantry equipment represents a catch-all for Battalion-level. The effectiveness of an infantryman's rifle is vastly less-significant at the battalion level (considering the reliability of standard bolt-action rifles like the Lee-Enfield or KAR 98) as opposed to the effectiveness of its anti-tank weapons, machine guns, or mortars.
For instance, an American infantry battalion's infantry equipment in 1944 consisted, excluding small arms, of 20 .30cal lmgs, 6x .50 hmgs, 9x60mm mortars, 8x81mm mortars, and 26 bazookas. At the squad level, you're looking at something like 9 M1 garands, an M1A1 carbine, an M1 Thompson, and a BAR (give or take a few depending on squad makeup). I'm having trouble getting the same stats for 1936 or 1939 equipment (the US Army unhelpfully barely existed in 1936), but you're often looking at almost 100% bolt-action rifles in infantry squads, and far fewer machine guns and mortars per squad (although infantry guns were proliferated oftentimes instead). More importantly, AT rockets didn't exist yet, and AT rifles were still fairly rudimentary in 1936 (most infantry had to rely on hand-held explosives like mines or AT grenades instead).
Then consider that a US squad with semi-auto rifles compared to a German squad with one or two LMGs as opposed to an autorifle evens out the firepower difference pretty drastically, and that certain nations had preference for different types of equipment throughout the war (such as the Soviets making larger numbers of SMGs than the Germans, who fielded large numbers of LMGs). Similarly, differences in the capabilities of something like a German battalion's 150mm infantry guns compared to American or British mortar sections are hard to nail down to anywhere specific.
Then consider the simple question of how to represent the above concerns within 13 technologies, representing the gap from 1918 to 1944 (not including night fighting). At some point, the strategic implications of semi-automatic rifles are fairly insignificant when you consider that the game doesn't represent such massive divisions as light versus heavy AT (37-57mm versus 75-128mm), artillery (75mm versus 150mm), or AA (20mm versus 90mm). Battleship guns are all equated as identical despite ENORMOUS divisions between something like a 281mm c/34 German gun and an American 16-inch Mk.IV gun (281mm has half the explosive power of most 305mm guns, let alone 406mm ones). Tank destroyers and SPGs don't upgrade with artillery tech, while regular guns do (i.e. 1918 artillery still benefits from the passive buffs in artillery research). The Bf 109 is technologically comparable to such awe-inspiring fighters as the I-16 (no supercharger, low speed, minimal power), the P-36 (obsolete before the war started), and the Hurricane (which deliberately avoided 109s in the Battle of Britain).
I'm not suggesting that small arms aren't impactful enough to affect the soft attack of a division, but I'd argue that the existing "Infantry Equipment" techs already represent a whole doctrinal shift rather than one or two upgrades. Infantry equipment upgrades show the proliferation of man-portable AT, automatic weapons, and explosives more than just the equipment of infantry squads.