@Bhadra, to put it simple, so you will be able to understand that (however I still have doubts, as you are incapable to understand anything...)
You are another, civilian, who don't know shit about military, weapon systems, or how military operates on battlefield.
Furthermore, similiar civilians to you, completely ignore a fact, that different militaries around the globe, purchase new tanks, be it used ones from surplus stocks, or invest money in to R&D programs, to develop new tanks. Examples:
Japan invested in to R&D to develop Type 10 MBT as replacement for older Typ 74 and supplement for Type 90 MBT.
South Korea, invested in to R&D to develop new K2 MBT, as well to modernize K1 to K1E1 standard and K1A1 to K1A2 standard.
China invested money in to R&D for new MBT, called ZTZ-99A2 (although real designation is not known yet). They also develop new larger, heavier and better protected platforms to replace the ones they use currently.
Israel invested a lot of money in to R&D for Merkava Mk4 MBT and also platform based on it like HAPC Namer.
USA invest a lot of money in to countinous modernization and production of the M1 tank, currently new variant is in development, and US Army also have plans to develop new MBT to replace M1 in future, not to mention that they also invest in R&D to improve other platforms, or develop a heavier, better replacement for them. I written that a lot in the past, but you as allways ignored this, however I repeat, because at some point knowledge should break through wall isolating your brain. Lightweight HMMWV will be replace by heavier, better protected JLTV, Strykers are modernized by replacing old, lighter armor FBH hull with new heavier armored DVH hull, M113 will be repalced by larger, heavier, better protected AMPV, M2 IFV will be modernized and in future replaced by new, larger and heavier IFV, M1 is modernized, it's protection improved, and in future it will be replaced by new MBT, and so on.
UK cancelled all ideas to decomission Challenger 2 MBT's, and now their modernization is in R&D phase. Also lightweight CVR(T) platform are being replaced by larger, heavier, better protected FRES-SV platforms.
Germany replaces older Marder IFV's with new, heavier, better protected Puma IFV's, also modernization of Leopard 2 tanks to Leopard 2A7 which is heavier, better protected variant is pending, also many other types of platforms in Heer, is replaced by new, bigger and heavier replacements. There is also discussion in Bundestag to restart production of Leopard 2 tanks, and even to restart program for new Leopard 3 MBT.
France Leclerc MBT modernization program is pending, also older lighter and weaker protected platforms are now replaced or waiting to be replaced by newer, heavier and better protected platforms.
Russia have program "Armata", "Kurganets-25" and "Boomerang" to develop larger, heavier and better protected replacements for all currently used tracked and wheeled combat platforms.
Poland, my own country also have it's own programs for AFV's modernization and procurement, we purchased 250 Leopard 2 tanks and their modernization program will start soon. We also have R&D program for new larger, heavier and better protected IFV to replace BMP-1's. And there is many more.
Turkey, they have their own MBT R&D program Altay, they also developed new heavier, better protected IFV Tulpar as their universal tracked platform which is in R&D phase.
I could probably spend a whole week writing about all these programs. And how many programs to develop new attack helicopters there are? Few only.
There is good reason why there is more tanks than fighter jets or attack helicopters. Tanks are cheap, and in many ways more effective on battlefield than attack helicopters or fighter jets.
In general civilians like Bhadra with 0 knowledge and such matters should be quiet and stop creating their sick ideas that will harm armed forces.
But there is good news, armed forces of all nations, preatty much don't care about opinion of civilians like Bhadra, and invest money on more, heavier, better protected, larger armored fighting vehicles, because this is what they need.
Also one more interesting point, here in Poland we have a program to find replacement for Mi-24 attack helicopters. However because we don't have enough money for all modernization program to be finalized at once, so prioritizing these programs is nececary. And guess what, general consensus is that attack helicopters procurement program should have low priority, why? Because all analisis from modern battlefields show, that attack helicopters, or helicopters in general, have very low combat efficency, and have very low survivability.