For starters, you can't expect to be getting to final table in large MTTs very often even if you are a skilled player, because it requires a lot of luck regardless. You will likely have to survive at least a few all-ins, at which point it just comes down to maximizing your
odds and hoping for the best.
However if you find that you're specifically busting out in the final 2-3 tables, it may just be that you aren't transitioning properly from early to late tournament playstyle. Standard early MTT play is usually straightforward tight-aggressive to counter all of the loose/reckless players that you encounter early on, but once you get deep these players have all been picked off, and most of the remaining field will be actively strategic players.
At this point you will also likely be sitting at a table with the same players for a while, as there's less shifting around due to eliminations, so it becomes very important to start taking notes on your opponents' habits and transition to more exploitative play. A lot of smart players will excel here in picking good spots to
bluff tight opponents who are mainly playing to ladder; don't be one of those easy targets. Play to win and take calculated risks, even if it means you might only barely crack the bubble rather than floating to 20-30th. This will protect you from being sniped by those players, and will make you more money in the long run when you get those big wins late in the game.