If there's a dispute, a 3rd party might help solving it: hence why escrows still survive. Also, multisig technology doesn't need to replace escrows. Both can co-exist.

You simply can't because it's not possible to represent "every" transaction in decentralized manor. Certain things can through the use of smart contracts and as these become more powerful and able to interact cross chain we may see new potential, but the two must always co-exist. There will never be a point where mediation of a 3rd party isn't a good thing to have.

Deals can be very complex and require human moderation. Multisig is without question a great invention, but it won't make escrow irrelevant. Smart contracts will neither, because these contracts are not able to automatically set in motion a transfer of real world objects.

Imagine a buyer and seller agreeing on a multisig address. Now the seller transfers his goods to the buyer, but the buyer refuses to agree on a transfer of funds, until the seller gives him something extra. Only an independent third party would be able to properly resolve this case.

In fact, a 2-of-3 multisig setup could improve the usage of human escrow, because it would reduce the risk of getting scammed by the escrow provider himself, who alone can't control the funds.

ya.ya.yo!

Escrow is always necessary due to the fact that 2nd party might not deliver the coins after receiving the product. That's when a 3rd party enters in game. No automatic system is 100% effective, there must be always a human system to solve these kind of problems.

2-of-3 multisig escrow system MAY work if the escrow is trustable. The escrow can easily act as the seller and if the transaction value is high enough, the escrow can run with the funds since he will control 2 of the 3 keys. Even though multisig does help to reduce the risk of the escrow scamming, it is still very possible. 2-of-2 escrow system wouldn't work since either party and refuse to sign.

Escrow is not needed at all, but a reputable third person is still needed for arbitrage.
So a 2 of 3 multisig, where the third key owner can mediate the issues if they occur is the way to go.

2-of-2 multisigs don't really help solve a dispute since there's no way the parties involved would be able to solve it(unless they could come up with an agreement in which case they would just release the bitcoins and product to each other). Escrow is a third-party trader that help prevent disputes and solves them if one crops up.

This may only come true if the escrow remain trustworthy throughout the process and don't become biased in middle which is quite rare and OP is also having fear about escrow turning into scam. However there is no other choice in most of the cases so even it is risky use of 2 of 3 multisig addresses with escrow in middle is the only thing that can help in deal between two parties. In future smart contract may solve this problem but it still needs much more time.