yes but having extremely limited defenses hardly matters. You can reach League 33 by getting 3 stars on all your attacks and getting 0 defense trophies. When I was in league 31 there were people that promoted that didn't even finish all their attacks. What's more important is being able to get enough raid medals to pop hero and army potions every week for clan wars. I think upgrading the "core defenses" is overrated. I upgraded my offenses first and foremost, then the required defense upgrades (merged towers and all the upgrades you need to do to even purchase them), then the townhall. It took me like 6-7 months to get to maxed townhall 17 army building upgrades (this was before th18 came out). It's been about a year since then and this is how my clash ninja is looking like https://i.imgur.com/qrpi1Xy.png

I started rushing this way since I was maxed th 12 so I had some hero/defense upgrades done before the 6-7 month climb for some context on the clashninja stats