That 150,000 clicks is the same as the 5DII and 7D. A few years ago, that was the rating of the 1D series shutters and the "lesser"models were around 50,000 to 75,000. More recent 1D series have been rated at 300,000.... the 1DX is the first to be rated to 400K.
150,000 is actually a lot and should be fine unless you go crazy with it.
If you are a heavy user, get two and spread the usage around. My two 7Ds are three years old now and between them have close to 150,000 clicks... but each has only half that. But a big part of that is using the high frame rate for action shooting. My 5DII is even older and has less than 20,000 clicks on it, but I use it for much more sedate shooting purposes and rarely even use the 4.5 fps option at all. At the rate I'm going, if the shutter life rating is correct, I should still be using it in 2028 or 2029. I expect I'll be replacing the 7Ds much sooner.
Besides, shutter life is just an estimate. Check out the data someone has collected here on 5DII. Out of about 600 cameras reported, 87% met or exceeded the 150,000 click rating and 78% did double that or more. I discount the ones that were essentially "dead out of the box" (took under 6500 clicks so were probably repaired or replaced under warranty) and those reported to have done over 1,000,000 clicks (hard to believe). Still, the overall reliability looks quite strong.
And even if you take 150,000 shots a year and the shutter dies, spend $300 to replace it. If you are taking 150,000 shots a year or two, you are already spending lots of money on other things... memory cards, hard disk storage space, computer time, replacement batteries and chargers, worn out lenses... i.e. the general costs of shooting. If you are taking 150,000 shots every year or two, hopefully you are making some money off them that will help pay for the repairs.
I voted "other". I only upgrade when the new model meets some need I'm encountering. For example, one of the primary reasons I bought my 7Ds and 5DII was high ISO performance compared to earlier models I'd been using. The 7Ds gave me about an extra stop and the 5DII is good for about two, compared with what I was using before. There were plenty of other considerations, durability and "survivabliltiy" thanks to build quality was among them, and the shutter rating is part of that... but far from the top of my list of things to worry about. OTOH, what some might consider little things can make or break a camera choice... For example I never bought the 5D classic because of it's reputation as a dust magnet. I often have to shoot in dusty situations and already was cleaning my 30Ds' sensors far more often than I liked. The self-cleaning sensors of the 50D proved to be very effective and useful when I used those, so the 5DII was a great choice. The way I use my cameras, I'm not rushing out to get the 5DIII, but imagine I will some day. Or maybe I'll try the 6D.