I can think of lots of reasons. For example:
On a short trip, the time to climb can be longer than the en-route bit itself. For an instructor giving a 1-hour lesson, the student would be short-changed if the first 10 minutes was spent climbing. Anyone using MoGas will be limited to 6000' by PFA rules. Anyone flying cross-country using a Plog will find that they are behind schedule the whole way unless they treat the climb as a seperate segment, which might be off-putting for low-hours pilots or students. Some people prefer the view from lower down. Others prefer the increased sensation of speed from lower down. Then there's the fear that the clouds will build up and you'll be trapped on top of an 8/8 layer. The fact that things look different from higher up, and many people will never have seen that before (due to the reasons I gave earlier about instructors not wanting to waste time climbing) so may be put off by it. I'm sure there are more, too!
All good reasons. Some of them are good enough to out-weigh the advantages of climbing, others aren't... but the best thing that people like Lowtimer can do is keep quiet and let the rest of us fly low down, so that he can have the higher levels completely to himself!
FFF
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