JMO, but every T1 should have a long-acting insulin RX “on file” - if your pump dies over a weekend, or even worse, over a holiday weekend, you could need to go back to MDI for a few days. It’s better to have easy access to long-acting insulin than to have to scramble to figure something out (since odds are good if you can’t get a new pump next day, reaching your doctor won’t be possible either)
Your desire to go back on MDI for a pump break has little to do with this… it’s really a safety concern. If you have seen your endo relatively recently, you can just ask them to call in an RX for you - I really can’t see why they wouldn’t. You can even say that you had an issue with your pump that made you nervous about NOT having any long-acting, and they probably won’t even question it. If it’s been a while since you’ve been and you don’t want to deal with going to see them, urgent care will also give you an RX as well. albeit at probably a higher co-pay than seeing your endo, but they will write it for you (probably for only for one month though).
Personally, as a pumper, I love having the flexibility to do whatever I want - if that’s MDI, great, if that’s POLI, also great, and if that’s 100% pumped insulin, again, also great - it’s all my choice. Not great is not having access to the insulin you need.
Short of that, check your local Craigslist… I’ve been able to find Lantus for FAR less than my RX co-pay would be (because it’s Tier 3 and my insurance only covers Levemir at Teir 1, which I am allergic to). I’ll only accept unopened boxes (vials or pens) from strangers though - it’s never a good idea to accept a single pen since they can’t be guaranteed sterile/unused.