Why is Toronto trading for 31 year old Jeff Skinner with 4 years/$9 mil AAV left on his contract? Couldn't they pay a bit more to re-sign the younger Nylander?

Leafs spend 9m elsewhere and keep the pick instead of trading for Skinner. By your post, the Sabres still have lots of cap for Skinner.
Skinner's NMC might be a tough trade for the Sabres. Skinner would only want to go to a good team, and those teams have no cap.

Don't think Toronto switches from Nylander to Skinner next offseason but unloading Skinner after his recent success sounds like a good idea. You could trade him to a team looking to save some real money while looking to add a top six guy as Skinner is only paid 7 and 5 million real dollars in the last two years of his deal. Maybe Detroit is a landing spot? Perron's contract is up and it's yet to see if Sprong's a one year wonder so there's a vacant spot on the second line. Vancouver is also a landing spot as he could come in and replace Beau on the second line. Is Anaheim looking to compete? With Henrique and Silverberg out and a ton of cap space it could be a fit.
Maybe retain a little bit too bring to 8 and you get a good return?

Probably the route the Leafs go just thought If things did fall apart this could be a decent fall back option.

No one is going to touch that contract unless Buffalo retains

We don’t have the cap or the desire

As I've mentioned higher in the thread an internal cap team could be looking to acquire him. He's only paid 7 and 5 million real dollars so at that mount he's really only a cap problem more than anything.

Skinner apparently wanted to stay close to toronto, when he was due for a contract, toronto had no cap space and may not have had any interest. Buffalo was the natural landing spot, unless he really wanted to expand his idea of "close to toronto". The irony to me, is Skinner had earned a reputation as a stick tapper that didn't put any effort into getting back, AND he had limited himself to pretty much only playing in buffalo. And somehow, his agent managed to get 8x9, which is astounding considering his market value was probably between 6.5 and 7, and he had absolutely no leverage.

Not really lul we can do better

If Nylander leaves in FA leafs can then go after someone like Debrusk, Eberle, Lindholm, Tarasenko, Toffoli, Arvidsson, all of whome will cost less and are better options

Or sends a nice sweetener. Send Kulich then maybe we got something

Lindholm is the only “better” option but depends what the leafs value