I think we should simply be mindful to factor in shutter replacement costs as part of the operating costs of cameras. Other than the usual lemons and catastrophic failures at the most inappropriate times, most modern cameras have shutter durability specs that the casual snapper will believe can last a lifetime. Of course the professional photogs know otherwise
$300 for a shutter rated at 150,000 to 200,000 is quite reasonable. Bearing in mind that there is little else in terms of running cost for modern day digital cameras. Perhaps factor in an additional yearly replacement of rechargeable batteries. There is no film cost, no development charges.
During the film days, how much would one spend on just <20,000 shots. Let's think 36-exposure films @ $4-5 a pop, plus $2 development, plus print. Using 500 rolls which would have cost >$3K will only get you 18,000 shots.
I remembered having replaced my Leica film body's 'cloth shutter curtain' twice for not much less than CSC rates today; and they lasted for less than 500 rolls of film I'm sure.
Just as there must be regular parts change in running another popular mechanical device - the gas-guzzling, ERP sapping & tempers trying CAR - think oil change, spark plugs replacement, tyre wear, flat batteries, blown bulbs, etc; I would advocate heading off to your camera service center for a shutter mechanism change if you're lucky enough to hit 75% of the spec'd actuations.
Replacement cost: $300
Not having a shutter fail mid-assignment: Priceless!