This is player responsibility. You had the choice to buy the game/skins on whatever system you chose. Nobody but you and your living situation decided what hardware you played the game on.
While it would be nice if they had the ability to transfer your items this i can agree on. But it is in no way “unfair” you played the game on whatever you did at the time.
Thats like being upset someone got a pre-order bonus and you got the game 3 years later. Those skins and special extras in any game not just overwatch, are meant for special appeal at the time of their release. It is 100% up to the developers to decide to make them available or not later. In fact in most cases making items that were limited before repeat or become all access hurts the company more, because while it makes people who didnt have them before happy it makes it clear the company will not stick to their words and promises and they lose all faith and face value with new releases.
The only limited skin that needs to be available again is the Sombra Demonhunter. This is because the devs made a promise it would be available without a Blizzcon ticket purchase in 2019. After they make it available once more it should be vaulted again forever, but this is only because alot of people (like myself) were willing to pay $50 just for that skin, but they made it clear we didnt need to pay $50 for that skin cause they were gonna make it available in the coming year. Though they never said when, how long, or how to abtain it.
Basically just like reverting a limited to all access, promising a limited skin and not providing hurts their credibility.