There are many solutions.

For example - allow ticket resale only through the official platform and cap it at the original sale price.

Another approach - check IDs at the door and only let the original ticket purchaser through.

The real problem is that scalping is insanely profitable for Ticketmaster & co. They take a cut of the original sale and every subsequent transfer, most of them at highly inflated prices, from both buyer and seller. Why would they give that up?