I can understand that Styg but let me put it in this perspective. How worth is it going to be to add a very rare component to a gun (assuming you even have the skill to put it on the gun if it's something that rare) if at the end of the day the gun's damage is going to be that much inferior to the damage of a gun that the merchant sells me?
If you found some low quality component early game, crafted a gun out of it and then traveled to say Junkyard and compared it to the higher level gear there, that's not enough to draw a conclusion that all crafted gear is inherently worse than what's available for purchase.
The equipment that the merchant sells is typically of the same level as the components the merchant sells. The equipment that the merchant sells is generated by using the same blueprints that the player uses when crafting and is crafted out of components of the appropriate level. So you see, the crafted equipment is not inferior in stats, it's actually, on average, the same level. Same goes for loot you find.
That about puts the crafting and purchasing on the same level power wise. The reason why it would be beneficial to a character to spend points on tech skills is as I stated in the previous posts - blueprints and components that are exclusive for crafting, or just very rarely found in a finished product. Not to mention that the crafting is both a cheaper way to obtain gear, can create profit when selling and can be used to craft consumables and such.