Why people look
Almost nobody searches for SiteGround alternatives because the hosting stopped working. They search because the second-year invoice arrived. That matters, because it means the question is not “what is better”, it is “what am I willing to give up to pay less”.
If you were paying for support
This is the honest reason SiteGround costs what it does. Support answers technical questions rather than deflecting them. Moving to a budget host means moving that work onto yourself. Budget accordingly, in time rather than money.
If you were paying for the tooling
Staging, daily restorable backups and a first-party caching plugin remove a lot of hosting admin. Some cheaper hosts include staging on mid tiers. Most do not include the caching integration, so you will be configuring LiteSpeed Cache or similar yourself.
If you just need the site online
For a low-traffic site with no revenue attached, almost any competent shared host will do, and the money saved is real. Be honest about which category your site is in before choosing.
How to compare properly
Compare year two, not year one. Compare the visit or resource cap, not the storage number. And check whether staging and backups are included or sold separately, because that gap is where the price difference usually hides.