As a new TH11, especially with such rushed defenses, you’ll expect to be crushed in defense on a daily basis, but what I experience is a complete opposite:
There is really no evidence that I’m performing poorer compared to someone who maxed TH10 previously. And I’m comparing using my own mid and maxed TH11 accounts, this account is not performing worse than my other accounts. In fact, it is doing better because I get easy shields and not much collector loot loss. My other accounts actually lose more due to <30% attacks so I am attacked a few times before someone strong comes to wreck my maxed TH11 base.
In 10 days as a new TH11, I have gotten 24 defenses and around 8 are considered 100% losses. Its quite a bargain really, I might lose slightly more loot than a maxer, but they have wasted 400-600mil more gold than me and years of their play time. Just to get a small advantage which does not pay for the costs. Its much better to spend that 400-600mil + years to work on more important things such as maxed TH11 troops and maxed warden. Why bother upgrading defenses when they do not give much benefit and may give harm when you farm in lower leagues?
Furthermore, in higher leagues, all the advantages of maxing defenses means squat when everyone can easily crush your base. If you plan on high league farming like most forumers or redditors recommend, then defenses mean nothing because you will be crushed either way with 4-5 defenses upgrading.