The majority of poskim are mattir natural wigs.
Is it modest to wear an attractive tichel?
You can repeat the alleged psak from R’ Elyashiv as many times as you want, but it’s certainly not the accepted one.
Are there immodest wigs? Sure there are. There are also immodest tichels and hats and all articles of clothing (even if they give full coverage), but a blanket statement that a natural statement is inherently immodest is incorrect.
Again, if real looking hair we’re inherently immodest, single girls would have to cover their hair.