Infinity evolved doesn't even have an iguana style tiering system though. Once you get alumite, you have access to pretty much any ticon material, but no vanilla style tools really. Once you have a ticon setup, including a small smeltery, which is at minimum 36 seared bricks and 5 glass, which is not hard to get at all, you have access to copper, tin, bronze, iron, alumite, steel, electrum, invar, and probably more. There are no material tiers beyond stone, iron, diamond, alumite. One steel ingot and a small smeltery and you can harvest any material you want. Before you even get steel you can alloy lava and water to get obsidian for alumite! And that doesn't even require an iron level pick! No coke oven or blast furnace, no diamonds. Just a regular stone or flint pickaxe.
Anyways the point I'm trying to make here, is it's clearly not a balancing decision. You don't have to worry if a player with a vanilla style shiny or diamond pick is any better than someone using tinkers because the tinkers player doesn't even need to make an iron level pick while the vanilla style player absolutely does. Alumite is around the same level as a vanilla diamond pick, just with less durability. It's also much cheaper at the cost of aluminum, iron, and obsidian, along with the tech costs of some sand, gravel, and clay, as well as a single bucket to scoop lava with. The tinkers user will win out as more powerful every time with the current setup. So why disable vanilla type tools as opposed to tweaking them?
Specifically to the waste of resources comment: Why would vanilla tools being a waste of resources matter at all in a packmaking scenario? To the player yeah it's a waste. To the developer, if anyone cares about resource waste they'll go with the cheaper version.
And the fact that vanilla ticon is more balanced isn't really a decent argument either because it does have extraTiC. It is overpowered as hell, and the by comparison entirely underpowered vanilla tools become nerfed for some reason.
Allowing vanilla tools wouldn't break ticon progression if you tweaked them to follow ticon progression instead of tweaking them to be unavailable for use. Which wouldn't even be too hard. Just use certain smeltery parts in the recipe, like for example make an iron pickaxe require 3 iron, an iron binding, and a stick. It still requires a smeltery and follows ticon progression, but doesn't require the player to actually use a ticon tool. Instead it integrates the vanilla tool system into tinkers construct.
I prefer vanilla tools because I happen to like them better. Having to make a new tool every once in a while isn't a problem for me. It's personal preference. I also think the tinkers tools are too powerful and using only vanilla style tools makes for a more unified experience, and encourages the use of modded tools like the terra shatterer, the mining drill, primal smasher, kami, etc. I'm not saying that tinkers is bad or should be removed, I'm saying I'd like the choice to use the type of tool that I like. It's just too easy to get a really powerful tool in tinkers for my taste. So I'd at least like the option to not use them.