Well depends which brand of stroller and whether it can be folded to a very compact form and the weight is needs to taken in factor, if over 10kg and hard to be made in a compact form which can be handled by one hand, then it's not good for public transport
But something like combi spazio folds length wise then width wise, with one hand, Easy to take on public transport
No idea what the first line means.
Are you talking about the old fashioned non-folding prams or the folding version? If the latter then we did buses and taxis. Trams would I agree be impossible and mini buses bloody difficult but you easily get around most places without using those.
Hip seat(brand) is a variant of strap on baby carrier, difference between this and traditional baby carrier is that traditional baby carrier weight distribution is mostly on the shoulder with support on the weight, but weight distribution is solely on the shoulders, ok for small babys, not good to use for a longer period for toddlers
Hip seat distributes the weight of kid more on the waist so you can carry longer and tiresome, so heavier toddlers are fine or very long period carrying the baby
There is only one type of baby carrier that's better than this, it's heavy duty and expensive hiking baby carrier, like a heavy duty rucksack
Lots of stuff in our classifieds - some of the items may be cheaper to buy than renting.
https://geoexpat.com/classifieds/baby-kids/
I loved the hip seat, we actually use it without the restraining bit, as both my babies/toddlers wanted to get off and walk all the time and then hop back on It Was very convenient. My back and arms couldn't survive holding them without using a hip seat for longer than 5 mins but with the hip seat i could carry for hours, it was great for stroller unfriendly places. No experience with ergo though.
As for rental vs buying. My sis in law rented as unfortunately we just got rid of our cot and highchair, we thought about buying but I seriously could do with having space in my apartment plus you never know when they grow out of a cot. My first one was in the cot till almost 2.5 yrs and my second one only lasted there 1.5 yrs (started climbing out). Renting was easy they delivered and picked up. No hassle and more importantly more space at home.
Beer belly replaces the hip seat for me