Yes, and airliners occasionally crash, but you don't insist on wearing a parachute and O2 mask everytime you board a 747 do you?
As says the hostess, in case of depressurization (I always love how kindly they say that), an oxygen mask will fall right in front of you.
What they don't say is that you have only 10-12 minutes of O2 but well, much better than nothing.
And, provided there are no "dangerous" parts inside and that it can fit in the cabin luggage format, I think nothing prevents you to carry your own parachute :bailout:
Something tells me that it would require advanced technology materials to fit the size and mass constraints but that's certainly not undoable...
Back to the topic, launch a capsule nowadays without a functional LES is out of question. In the history of manned spaceflight, it was done only with Voskhod 1 & 2, and that was stupidly dangerous. Nikita Khruchev was very very lucky that nobody died during those two flights, and even more that Alexei Lenov performed and survived the EVA.
Now yes, there is the Shuttle case, which had a 'gap' in the abort sequences. The interesting fact is that, even if the cabin could have been separated and boosted away when the Challenger disaster happened, that would probably not have helped. The SRB toric joint failure was unoticed by sensors and even cameras until the disaster happened. Say they had put an Apollo capsule with a LES tower on top of the STS instead of the Shuttle on the side, would the crew had been saved ? Maybe, maybe not... But if the flame getting out of the SRB had been noticed, it would have let enough time to shut down the SSMEs and detach the Shuttle, no ? So the crew would have had a chance to land or bail out. So, I'd say it was more an instrumentation problem. Columbia was a basically a thermic shielding failure, and capsules can nothing against that either. The difference is that it is much easier to make sure that the shield is in perfect shape before launch, and also the fact that it is safely encased until the re-entry capsule is separated.