so, a bike consists in a frame, wheels and other components. among those other components, you have gears and brakes. those are usually made by Shimano or SRAM. here are their quality ranges. for Shimano's "MTB" groupsets, take at least Deore. your Ridgeback Element has low quality component and thus I personaly eliminate it from any selection.
bike brands mostly make frames and choose components. some brands "make" shitty frames (e.g. I recently saw a misalined fork but there are other quality issues) and offer a broad range of components, so a custommer with a low budget finds a bike and a custommer with a high budget can be milked with good groupsets to justify it.
if you are willing to invest 1500 EUR (or more, which would be worthwile), don't be milked with good groupsets and shitty frame/wheels. how? avoid brands that are willing to sell anything. the brands I mentioned seem safe in that regard (there are other such brands in the EU btw).
Life time (Will it just last three times as long?) should be defined, but yes, a new bike from a quality brand, costing 1500 EUR, will cost you <1/3 than a 500 EUR new bike, in terms of cost-equivalent in worries, effort, wasted time, maintenance, repairs etc. over 15 years. performance is also affected, especially past the 1st year I'd say.
why it's difficult to compare? because some companies drown custommers in information that pushes them to make a purchase with a maximized margin.
btw for Patria, I only know that in a French shop near Basel, the Terra model costs 2060 EUR in LX groupset and the Argos model costs 2210 EUR in LX groupset. those aren't exactly (although could be) what you're looking for, but if someone knows the price in other shops, I'd be interested to compare.
