As someone who has a scythe on Normie EIM and GIM I will not support this suggestion. On normie I have maybe 70kc and earned around 800 vials. EIM I have around 225 ish kc with nearly 3k vials from that. GIM I have roughly 100 kc and around 1.7k total vials on that. Yes we like to offer ease of access things compared to osrs but the Scythe of Vitur is a very prestigious weapon if not THE MOST prestigious weapon.
And as such it should come with a cost as many other individuals have said here. But adding the "fuel" of the highest tier melee weapon to a shop that can be considered "infinite " would cause detrimental devalue to the Scythe itself.
As
iron aritus
said vials were never the problem to the weapons that required them. It was the blood runes that was the bottleneck to this problematic conundrum. This has since been "fixed" .
Though I can see your point and understand where you're coming from the addition of a shop with vials of blood just seems like the best way to devalue TOB more than what it is currently. There are a multitude of reasons I would never support this suggestion but I would be rambling for hours about this.
If you take my drops into account 800+3000+1700=5500~ vials of blood in 400~ raids = 13.75 vials of blood per TOB. Now a standard TOB time to complete is around 18-20 mins if you have a team that's half decent at mechanics. So 42 vials an hour equates to 12,375 blood runes. The Scythe has an attack speed of 5 with 3 second intervals. So in theory you would use "ROUGHLY" 40k charges an hour if you hit non stop the entire time. Now divide that by 100casts per one vial that's 400 vials for an entire hour.
This is where I would somewhat agree with you on putting them into a shop. But at the end of the day it would devalue the Scythe of Vitur DRASTICALLY.
I'm sorry but if you want to use the most powerful weapon as much as you'd like. I would camp the trading post and no life TOB just like everyone (Normie and all Ironman modes) do.
Have a great day