I understand your view on paying that much for an event. Just realize that everything in life is relative... including money. To most people $500 is a lot of money... to others it's chump change.
For example:
Everything I own has been paid off for several years including my home and 2 rental properties.
I have a good job and still work 50+ hours a week (in fact, I'm there now 🙂).
CAN I afford to drop the money needed to buy the 150 ancient shards and get Staltus, sure, no problem. It would not affect my financial situation at all.
WOULD I spend that much on shards just to get a guaranteed digital Legendaryin a mobile game? HELL NO.
Honestly, if you want to participate in this game you have 2 choices:
A.) Do your RESEARCH, make a plan for yourself, and USE SELF CONTROL TO STICK TO THAT PLAN. For example, You SAVE your shards and pick the events that you want to participate in. Don't impulse spend shards on every event that pops up. For example, I pulled ancient shards earlier this week in order to get double Legos. Since I keep up with my shard count so I knew how many shards I needed to pull to guarantee that I would get those 2 Legendaries. (They ended up being crap Legos but that's the way this game goes.) I already knew there was going to be a guaranteed Legendary event this weekend and I already know we are due for a 2X Ancient event on the 25th... I decided that the CHANCE of pulling 1 or 2 good Legendary Champions outweighed spending 3X more shards I would need to get Staltus.
B.) Spend a crapload of real money and attempt to buy your way through this game.